Datasheets | Application Specific for Automotive | Car Entertainment ICs | Signal Processors

Car radio signal processor

Datasheet

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Last Updated: 19/09/2008

Pages: 69

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TDA7402
Car radio signal processor
Features

3 stereo inputs 3 mono inputs Dynamic-compression-stage for cd Soft Step volume Bass, treble and loudness control Voice-band filter Direct mute and Soft Mute Internal beep Four independent speaker-outputs Stereo subwoofer output Independent second source-selector Full mixing capability Pause detector
LQFP44

Digital control

I2C bus interface

Description
The device includes a high performance audioprocessor and a stereo decoder-noise blanker combination, with the whole low frequency signal processing necessary for state of the art, as well as future car radios. The digital control allows a programming in a wide range of all the filter characteristics. The stereo decoder part also offers several possibilities of programming, especially for the adaptation to different IF devices.

Stereo decoder

RDS mute No external adjustments AM/FM noiseblanker with several trigger controls Programmable multipath detector Quality detector output Device summary
Order code TDA7402

Table 1.

Package LQFP44 (10x 10x 1.4mm)

Packing Tray

September 2008

Rev 6

1/69
www.st.com 1

Contents

TDA7402

Contents
1 2 3 Pin connections and block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Audioprocessor part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.1 3.2 Audioprocessor part features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Input stages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.2.1 3.2.2 3.2.3 3.2.4 3.2.5 Full differential stereo input 1 (FD1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Full differential stereo input 2 (FD2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Mono differential input 1 (MD1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Mono differential input 2 (MD2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Single ended stereo input (SE1), single ended mono input (AM) and FM-MPX input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.3

AutoZero . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.3.1 3.3.2 AutoZero for stereo decoder selection . . . . . . . . . . . . . . . . . . . . . . . . . . 17 AutoZero remain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.4

Pause detector / MUX-output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.4.1 3.4.2 3.4.3 3.4.4 3.4.5 Loudness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Attenuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Peak frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Loudness order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Flat mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

3.5 3.6 3.7

Soft Mute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Soft Step volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Bass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.7.1 3.7.2 3.7.3 3.7.4 Attenuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Center frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Quality factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 DC mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3.8

Treble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.8.1 3.8.2 Attenuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Center frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

3.9 3.10
2/69

Subwoofer application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Voice band application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

TDA7402

Contents

3.11

Compander . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.11.1 3.11.2 3.11.3 Anti-clipping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Characteristic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 I2C bus timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

3.12 3.13 3.14 3.15 3.16

AC coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Output selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Subwoofer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Speaker attenuator and mixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Audioprocessor testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

4

Stereo decoder part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.1 4.2 4.3 Stereo decoder part features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Stereo decoder electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 31 Notes about the characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
4.3.1 4.3.2 4.3.3 4.3.4 Intermodulation suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Traffic radio (V.F.) suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 SCA (subsidiary communications authorization) . . . . . . . . . . . . . . . . . . 33 ACI (adjacent channel interference) . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.4 4.5

Noise blanker part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
4.4.1 Noise blanker part features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Multipath detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.5.1 Multipath detector features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

5

Functional description of stereo decoder . . . . . . . . . . . . . . . . . . . . . . . 38
5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 Stereo decoder mute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 InGain + infilter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Demodulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 De-emphasis and highcut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 PLL and pilot tone detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Fieldstrength control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 EVEL input and gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Stereo blend control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Highcut control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

6

Functional description of the noise blanker . . . . . . . . . . . . . . . . . . . . . 43

3/69

Contents

TDA7402

6.1 6.2 6.3

Trigger path FM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Noise controlled threshold adjustment (NCT) . . . . . . . . . . . . . . . . . . . . . 43 Additional threshold control mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . 44
6.3.1 6.3.2 6.3.3 6.3.4 Automatic threshold control by the stereo blend voltage . . . . . . . . . . . . 44 Over deviation detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Multipath level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 AM mode of the noiseblanker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

7

Functional description of the multipath detector . . . . . . . . . . . . . . . . . 45
7.1 7.2 7.3 Quality detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Testmode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Dual MPX usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
7.3.1 7.3.2 Feature description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

8

I2C bus interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
8.1 8.2 8.3 8.4 8.5 Interface protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Auto increment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Transmitted data (send mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Subaddress (receive mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Data byte specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

9 10 11

Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

4/69

TDA7402

List of tables

List of tables
Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Table 8. Table 9. Table 10. Table 11. Table 12. Table 13. Table 14. Table 15. Table 16. Table 17. Table 18. Table 19. Table 20. Table 21. Table 22. Table 23. Table 24. Table 25. Table 26. Table 27. Table 28. Table 29. Table 30. Table 31. Table 32. Table 33. Table 34. Table 35. Table 36. Table 37. Table 38. Table 39. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Attack times vs. soft-step times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Stereo decoder electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Noise blanker electrical characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Multipath detector electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Transmitted data (send mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Reset condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Subaddress (receive mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Main selector (0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Main loudness (1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Volume (2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Treble filter (3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Bass filter (4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Mixing programming (5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Soft mute (6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Voiceband (7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Second source selector (8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Second loudness (9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Subwoofer configuration / Bass (10). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Compander (11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Configuration audioprocessor I (12) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Configuration audioprocessor II (13) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Speaker, subwoofer and mixer level-control (14-20) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Testing Audioprocessor (21). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Stereo decoder (22) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Noise blanker I (23) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Noiseblanker II (24) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 AM / FM noiseblanker (25) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 High cut (26) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Fieldstrength control (27) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Multipath detector (28) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Stereo decoder adjustment (29) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Stereo decoder configuration (30) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Testing stereo decoder (31) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

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List of figures

TDA7402

List of figures
Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. Figure 20. Figure 21. Figure 22. Figure 23. Figure 24. Figure 25. Figure 26. Figure 27. Figure 28. Figure 29. Figure 30. Figure 31. Figure 32. Figure 33. Figure 34. Figure 35. Figure 36. Figure 37. Figure 38. Figure 39. Pin connections (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Input-stages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Loudness attenuation @ fP = 400Hz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Loudness center frequencies @ Attn. = 15dB. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 1st and 2nd order loudness @ Attn. = 15dB, fP=400Hz . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Soft Mute timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Soft Step timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Bass control @ fC = 80Hz, Q = 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Bass center frequencies @ gain = 14dB, Q = 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Bass quality factors @ Gain = 14dB, fC = 80Hz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Bass normal and DC Mode @ Gain = 14dB, fC = 80Hz . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Treble control @ fC = 17.5kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Treble center frequencies @ gain = 14dB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Subwoofer application with LPF 80/120/160Hz and HPF 90/135/180Hz . . . . . . . . . . . . . . 24 Voiceband application with HPF 300/450/600/750Hz and LPF 3k/6kHz . . . . . . . . . . . . . . 24 Compander block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Compander characteristic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Output selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Application 1 using internal highpass and mono low pass filter . . . . . . . . . . . . . . . . . . . . . 28 Application 2 using internal highpass and external stereo low pass filter . . . . . . . . . . . . . . 29 Application 3 using pure external filtering (e.g. DSP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Output selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Vn timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Trigger threshold vs. VPEAK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Deviation controlled trigger adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Field strength controlled trigger adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Block diagram of stereo decoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Signals during stereo decoder's Soft Mute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Signal control via Soft Mute pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Internal stereo blend characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Relation between internal and external LEVEL voltages for setup of stereo blend . . . . . . 41 Highcut characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Block diagram of the noise blanker. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Block diagram of the multipath detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Dual MPX input diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Application diagram (standard configuration) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Application diagram (Dual MPX mode). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 LQFP44 (10x10) mechanical data and package dimensions . . . . . . . . . . . . . . . . . . . . . . . 67

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TDA7402

Pin connections and block diagram

1

Pin connections and block diagram
Figure 1. Pin connections (top view)
MD1G/SE4L MD1/SE4R MUX/PAUSE ACOUTL ACOUTR

MD2G

MD2

44

43

42

41

40

CREF

39

38

37

SWINL

36

SWINR
35

SE1L SE1R FD1L+/SE3L FD1L-/SE2L FD1R+/SE3R FD1R-/SE2R FD2L+ FD2LFD2R+ FD2RAM

ACINLF
34 33 32 31 30 29 28 27 26 25 24 23

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

ACINLR ACINRF ACINRR OUTLF OUTLR OUTRF OUTRR OUTSWL OUTSWR OUTSSL OUTSSR

AM IF

MPX

LEVEL

MPIN

MPOUT

QUAL

SM

GND

SDA

SCL

VDD

D00AU1131

7/69

ACOUTL

ACOUTR SWINR SWINL

ACINRR ACINRF ACINLR ACINLF

8/69

Figure 2.

MUX SM

FD1L+

FD1LACIN VOICE BANDPASS + LOUDNESS TREBLE HP LP OUTPUT SELECTOR REAR SW BASS SOFT MUTE FRONT

FD1R+

FD1R-

FD2L+ IN-GAIN + AUTO ZERO SOFT STEP VOLUME

CHG

MONO-FADER MONO-FADER MIXER MONO-FADER MONO-FADER

OUTLF OUTLR OUTRF OUTRR

Pin connections and block diagram

FD2L-

FD2R+

AUX

MAIN SOURCE SELECTOR

Block diagram

FD2R-

INPUTMULTIPLEXER

SEL COMPANDER ANTI CLIP. INPUT

SER

MAIN

MIXING SELECTOR

MD1

MONO-FADER SUBWOOFER + PHONE CONTROL MONO-FADER

OUTSWL OUTSWR

MD1G

NAVI

MD2 MUTE IN GAIN LOUDNESS

MD2G

PHONE

SECOND SOURCE SELECTOR

OUTSSL

SEN

AM

OUTSSR

DIGITAL CONTROL

IIC BUS

SDA SCL

BEEP

PAUSE

MPX

80KHz LP

PILOT CANCELLATION 25KHz LP

DEMODULATOR + STEREO ADJUST + STEREO BLEND

S&H

HIGH CUT

PLL

PIL. DET.

QUAL. MULTIPATH DETECTOR D PULSE FORMER A SUPPLY

QUAL

VDD GND CREF AM/FM NOISE BANKER

AM-IF

TDA7402

MPIN

MPOUT

LEVEL

D00AU1130

TDA7402

Electrical specifications

2

Electrical specifications

VS = 9V; Tamb = 25C; RL = 10k; all gains = 0dB; f = 1kHz; unless otherwise specified. Table 2.
Symbol Input selector Rin VCL SIN GIN MIN Input resistance Clipping level Input separation Min. input gain all single ended Inputs 70 2.2 80 -1 13 0.5 Adjacent gain steps VDC Voffset DC steps GMIN to GMAX Remaining offset with autozero -10 6 0.5 10 mV mV -5 100 2.6 100 0 15 1 1 +1 17 1.5 5 130 k VRMS dB dB dB dB mV

Electrical characteristics
Parameter Test condition Min. Typ. Max. Unit

GIN MAX Max. input gain GSTEP Step resolution

Differential stereo inputs Rin Input resistance (see Figure 3) Differential 70 -1 GCD Gain only at true differential input -5 -11 CMRR eNO Common mode rejection ratio VCM = 1VRMS @ 1kHz VCM = 1VRMS @ 10kHz Output-noise @ speaker outputs 20Hz - 20kHz, flat; all stages 0dB 46 46 100 0 -6 -12 70 60 9 15 130 1 7 -13 k dB dB dB dB dB V

Differential mono inputs Rin CMRR Input impedance Common mode rejection ratio Differential VCM = 1VRMS @ 1kHz VCM = 1VRMS @ 10kHz Beep control VRMS Beep level Mix-gain = 6dB fBeep1 fBeep Beep frequency fBeep2 fBeep1 fBeep1 250 570 740 1.48 2.28 350 600 780 1.56 2.4 500 630 820 1.64 2.52 mV Hz Hz kHz kHz 40 40 40 56 70 60 72 k dB dB

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Electrical specifications Table 2.
Symbol Mixing control MLEVEL GMAX AMAX ASTEP Mixing ratio Max. gain Max. attenuation Attenuation step Main / mix source 13 -83 0.5 -6/-6 15 -79 1 17 -75 1.5

TDA7402

Electrical characteristics (continued)
Parameter Test condition Min. Typ. Max. Unit

dB dB dB dB

Multiplexer output (1) ROUT RL CL VDC Output impedance Output load resistance Output load capacitance DC voltage level 4.3 4.5 2 10 4.7 225 300 W k nF V

Loudness control ASTEP AMAX Step resolution Max. attenuation fP1 fPeak Peak frequency fP2 fP3 fP4 Volume control GMAX AMAX ASTEP EA ET VDC Soft mute
AMUTE

0.5 -21 180 360 540 720

1 -19 200 400 600 800

1.5 -17 220 440 660 880

dB dB Hz Hz Hz Hz

Max. gain Max. attenuation Step resolution G = -20 to +20dB Attenuation set error G = -80 to -20dB Tracking error Adjacent attenuation steps DC steps From 0dB to GMIN

30 -83 0 -0.75 -4

32 -79.5 0.5 0 0

34 -75 1 +0.75 3 2

dB dB dB dB dB dB mV mV

0.1 0.5

3 5

Mute attenuation T1 T2

80

100 0.48 0.96 1 2 170 600 1

dB ms ms ms ms V V

TD

Delay time T3 T4 70 200 123 324

VTH low

Low threshold for SM

Pin(2) 2.5

VTH high High threshold for SM Pin

10/69

TDA7402 Table 2.
Symbol RPU VPU

Electrical specifications Electrical characteristics (continued)
Parameter Internal pull-up resistor Internal pull-up voltage Test condition Min. 32 Typ. 45 3.3 Max. 58 Unit k V

Bass control CRANGE Control range ASTEP Step resolution fC1 fC2 fC3 fC Center frequency fC4 fC5 fC6 fC7 fC8 Q1 QBASS Quality factor Q2 Q3 Q4 DC = off DCGAIN Bass-DC-gain DC = on 4 4.4 6 dB +14 0.5 54 63 72 81 90 117 135 180 0.9 1.1 1.3 1.8 -1 +1 5 1 60 70 80 90 100 130 150 200 1 1.25 1.5 2 0 +16 1.5 66 77 88 99 110 143 165 220 1.1 1.4 1.7 2.2 +1 dB dB dB Hz Hz Hz Hz Hz Hz Hz Hz

Treble control CRANGE Control range ASTEP Step resolution fC1 fC Center frequency fC2 fC3 fC4 Pause detector(3) Window 1 VTH Zero crossing threshold Window 2 Window 3 IDELAY VTHP Pull-up current Pause threshold 15 40 80 160 25 3.0 35 mV mV mV A V +14 0.5 8 10 12 14 +15 1 10 12.5 15 17.5 +16 1.5 12 15 18 21 dB dB kHz kHz kHz kHz

11/69

Electrical specifications Table 2.
Symbol Speaker attenuator Rin GMAX AMAX ASTEP AMUTE EE VDC Input impedance Max. gain Max. attenuation Step resolution Output mute attenuation Attenuation set error DC steps Adjacent attenuation steps 0.1 35 14 -83 0.5 80 50 15 -79 1 90 2 5 65 16 -75 1.5

TDA7402

Electrical characteristics (continued)
Parameter Test condition Min. Typ. Max. Unit

k dB dB dB dB dB mV

Audio outputs VCLIP RL CL ROUT VDC Clipping level Output load resistance Output load capacitance Output impedance DC voltage level 4.3 30 4.5 d = 0.3% 2.2 2 10 100 4.7 2.6 VRMS k nF W V

Voice bandpass f HP1 f HP2 f HP3 fHP Highpass corner frequency f HP4 f HP5 f HP6 f HP7 f HP8 fLP Lowpass corner frequency f LP1 f LP2 81 122 162 194 270 405 540 675 2.7 5.4 90 135 180 215 300 450 600 750 3 6 99 148 198 236 330 495 660 825 3.3 6.6 Hz Hz Hz Hz Hz Hz Hz Hz kHz kHz

Subwoofer attenuator Rin GMAX AATTN ASTEP AMUTE EE VDC Input impedance Max. gain Max. attenuation Step resolution Output mute attenuation Attenuation set error DC steps Adjacent attenuation steps 1 35 14 -83 0.5 80 50 15 -79 1 90 2 5 65 16 -75 1.5 k dB dB dB dB dB mV

12/69

TDA7402 Table 2.
Symbol Subwoofer lowpass f LP1 fLP Lowpass corner frequency f LP2 f LP3 Differential outputs(4) RL load resistance at each output 1VRMS; AC coupled; THD=1% 2VRMS; AC coupled; THD=1% load resistance differential Capacitive load at each output 1VRMS; AC coupled; THD=1% 2VRMS; AC coupled; THD=1% CLmax at each output to ground CLmax between output terminals Output muted -10 1 2 2 4 72 108 144

Electrical specifications Electrical characteristics (continued)
Parameter Test condition Min. Typ. Max. Unit

80 120 160

88 132 176

Hz Hz Hz

k k k k 10 5 10 30 100 4.7 15 nF nF mV W V V

RDL CLMAX

CDLMAX Capacitive load differential VOffset ROUT VDC eNO DC offset at pins Output impedance DC voltage level Output noise

4.3 Output muted

4.5 6

Compander Vi < -46dB GMAX max. compander gain Vi < -46dB, Anti-clip = on tAtt1 tAtt Attack time tAtt2 tAtt3 tAtt4 tRel1 tRel Release time tRel2 tRel3 tRel4 VREF1 Compander reference input-level VREF2 (equals 0dB) VREF3 Compression factor Output signal / input signal 29 6 12 24 49 390 780 1.17 1.56 0.5 1.0 2.0 0.5 dB ms ms ms ms ms ms s s VRMS VRMS VRMS 19 dB

VREF

CF

13/69

Electrical specifications Table 2.
Symbol General BW = 20Hz - 20kHz output muted all gains = 0dB single ended inputs all gains = 0dB flat; VO = 2VRMS bass, treble at +12dB; a-weighted; VO = 2.6VRMS VIN = 1VRMS; all stages 0dB d distor tion VOUT = 1VRMS; bass & treble = 12dB 80 AV = 0 to -20dB AV = -20 to -60dB -1 -2

TDA7402

Electrical characteristics (continued)
Parameter Test condition Min. Typ. Max. Unit

eNO

Output noise

3 10 106 100 0.005 0.05 100 0 0

15 20

V V dB dB

S/N

Signal to noise ratio

0.1 0.1

% % dB

SC ET

Channel separation left/right Total tracking error

1 2

dB dB

1. If configured as multiplexer-output 2. The SM Pin is active low (mute = 0) 3. If configured as pause-output 4. If programmed as subwoofer diff. output

Table 3.
Symbol VS Tamb Tstg VESD VESD

Absolute maximum ratings
Parameter Operating supply voltage Operating temperature range Storage temperature range ESD protection (human body mode) ESD protection (machine mode) Value 10.5 -40 to 85 -55 to +150 2000 200 Unit V C C V V

Table 4.
Symbol Rth j-pins

Thermal data
Parameter Thermal resistance junction-pins max Value 65 Unit C/W

Table 5.
Symbol VS IS SVRR

Supply
Parameter Supply voltage Supply current Ripple rejection @ 1kHz VS = 9V Audioprocessor (all Filters flat) Test condition Min. 7.5 35 Typ. 9 50 60 Max. 10 65 Unit V mA dB

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TDA7402

Audioprocessor part

3
3.1

Audioprocessor part
Audioprocessor part features

Input multiplexer 2 fully differential CD stereo inputs with programmable attenuation 1 single ended stereo input 2 differential mono input 1 single ended mono input In-gain 0..15dB, 1dB steps internal offset cancellation (AutoZero) separate second source selector internal beep with 4 frequencies Beep, phone and navigation mixable to all speaker outputs programmable center frequency and frequency response 15 x 1dB steps selectable flat-mode (constant attenuation) 0.5dB attenuator 100dB range soft-step control with programmable times dynamic range compression for use with CD 2:1 compression rate programmable max. gain 2nd order frequency response center frequency programmable in 8 steps DC gain programmable + 15 x 1dB steps 2nd order frequency response center frequency programmable in 4 steps +15 x 1dB steps 2nd order butterworth highpass filter with programmable cut off frequency 2nd order butterworth lowpass filter with programmable cut off frequency selectable flat mode

Beep Mixing stage Loudness

Volume

Compander

Bass

Treble

Voice bandpass

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Audioprocessor part

TDA7402

Speaker 4 independent speaker controls in 1dB steps control range 95dB separate Mute single ended stereo output independent stereo level controls in 1dB steps control range 95dB separate Mute direct mute digitally controlled Soft Mute with 4 programmable mute-times programmable threshold

Subwoofer

Mute Functions

Pause Detector

3.2

Input stages
In the basic configuration two full differential, two mono differential, one single ended stereo and one single ended mono input are available. In addition a dedicated input for the stereo decoder MPX signal is present. Figure 3. Input-stages
SE3 SE2 FD1100K STEREO 15K 1 + FD1+ 100K 1 15K 15K 15K FD1/SE2 FD2 MD1/SE4 MD2 SE1 AM FM 100K MUTE IN GAIN MAIN SOURCE SELECTOR

SE3 15K FD2100K STEREO 1 + 1 100K 15K 15K MD2 SE4 28K MD1G 100K MONO + 28K MD1 FM BEEP MIXING SELECTOR MUTE MIXING STAGE 15K

FD2+

MD1 28K 100K SE4R 28K MD2G 100K MONO + SE3 28K SECOND SOURCE SELECTOR SE4R 28K

FD1/SE2 FD2

MD2 100K SE1 STEREO 28K 28K

MD1/SE4 MD2 SE1

MUTE IN GAIN

100K

AM FM

AM MONO 100K MPX 100K NOISE BLANKER + STEREO DECODER

D00AU1142

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TDA7402

Audioprocessor part

3.2.1

Full differential stereo input 1 (FD1)
The FD1 input is implemented as a buffered full-differential stereo stage with 100k input impedance at each input. The attenuation is programmable in 3 steps from 0 to -12dB in order to adapt the incoming signal level. A 6dB attenuation is included in the differential stage, the additional 6dB are done by a following resistive divider. This input is also configurable as two single ended stereo inputs (see pin-out).

3.2.2

Full differential stereo input 2 (FD2)
The FD2 input has the same general structure as FD1, but with a programmable attenuation of 0 or 6dB embedded in the differential stage.

3.2.3

Mono differential input 1 (MD1)
The MD1 input is designed as a basic differential stage with 56k input impedance. This input is configurable as a single ended stereo input (see pin-out).

3.2.4

Mono differential input 2 (MD2)
The MD2 input has the same topology as MD1, but without the possibility to configure it to single ended.

3.2.5

Single ended stereo input (SE1), single ended mono input (AM) and FM-MPX input
All single ended inputs offer an input impedance of 100k. The AM pin can be connected by software to the input of the stereo-decoder in order to use the AM noiseblanker and AM High Cut feature.

3.3

AutoZero
The AutoZero allows a reduction of the number of pins as well as external components by canceling any offset generated by or before the In-Gain-stage (Please notice that externally generated offsets, e.g. generated through the leakage current of the coupling capacitors, are not canceled). The auto zeroing is started every time the DATA-BYTE 0 is selected and needs max. 0.3ms for the alignment. To avoid audible clicks the Audioprocessor is muted before the loudness stage during this time. The AutoZero feature is only present in the main signal path.

3.3.1

AutoZero for stereo decoder selection
A special procedure is recommended for selecting the stereo decoder at the main inputselector to guarantee an optimum offset cancellation: 1. 2. 3. 4. 5. Soft Mute or Mute the signal-path Temporary deselect the stereo decoder at all input selectors Configure the stereo decoder via IIC-Bus Wait 1ms Select the stereo decoder at the main input selector first

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Audioprocessor part

TDA7402

The root cause of this procedure is, that after muting the stereo decoder (Step 1), the internal stereo decoder filters have to settle in order to perform a proper offset cancellation.

3.3.2

AutoZero remain
In some cases, for example if the P is executing a refresh cycle of the I2C Bus programming, it is not useful to start a new AutoZero action because no new source is selected and an undesired mute would appear at the outputs. For such applications the TDA7402 could be switched in the AutoZero Remain Mode (Bit 6 of the subaddress byte). If this bit is set to high, the DATABYTE 0 could be loaded without invoking the AutoZero and the old adjustment value remains.

3.4

Pause detector / MUX-output
The pin number 40 (Pause/MUX) is configurable for two different functions: 1. 2. During pause detector OFF this pin is used as a mono output of the main input selector. This signal is often used to drive a level/equalizer display on the car radio front panel. During pause detector ON the pin is used to define the time constant of the detector by an external capacitor. The pause detector is driven by the internal stereo decoder outputs in order to use pauses in the FM signal for alternate frequency jumps. If the signal level of both stereo decoder channels is outside the programmed voltage window, the external capacitor is abruptly discharged. Inside the pause condition the capacitor is slowly recharged by a constant current of 25A. The pause information is also available via I2C Bus (see I2C Bus programming).

3.4.1

Loudness
There are four parameters programmable in the loudness stage:

3.4.2

Attenuation
Figure 4 shows the attenuation as a function of frequency at fP = 400Hz Figure 4.
0.0

Loudness attenuation @ fP = 400Hz.

-5.0

-10.0

dB
-15.0

-20.0

-25.0 10.0

100.0

Hz

1.0K

10.0K

18/69

TDA7402

Audioprocessor part

3.4.3

Peak frequency
Figure 5 shows the four possible peak-frequencies at 200, 400, 600 and 800Hz Figure 5.
0. 0

Loudness center frequencies @ Attn. = 15dB.

-5.0

dB
-10.0

-15.0

-20.0 10.0

100.0

1.0K

10.0K

Hz

3.4.4

Loudness order
Different shapes of 1st and 2nd-order loudness Figure 6. 1st and 2nd order loudness @ Attn. = 15dB, fP=400Hz

0.0

-5.0

dB
-10.0

-15.0

-20.0 10.0

100.0

Hz

1.0K

10.0K

3.4.5

Flat mode
In flat mode the loudness stage works as a 0dB to -19dB attenuator.

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Audioprocessor part

TDA7402

3.5

Soft Mute
The digitally controlled Soft Mute stage allows muting/demuting the signal with a I2C bus programmable slope. The mute process can either be activated by the Soft Mute pin or by the I2C-bus. This slope is realized in a special S-shaped curve to mute slow in the critical regions (see Figure 7). For timing purposes the Bit0 of the I2C bus output register is set to 1 from the start of muting until the end of de-muting. Figure 7. Soft Mute timing
1

EXT. MUTE

+SIGNAL

REF

-SIGNAL

1 I2C BUS OUT
D97AU634

Time

Note:

Please notice that a started mute action is always terminated and could not be interrupted by a change of the mute -signal.

3.6

Soft Step volume
When the volume level is changed audible clicks could appear at the output. The root cause of those clicks could either be a DC offset before the volume stage or the sudden change of the envelope of the audio signal. With the Soft Step feature both kinds of clicks could be reduced to a minimum and are no more audible. The blend time from one step to the next is programmable in four steps. Figure 8. Soft Step timing
VOUT 1dB

0.5dB

SS Time -0.5dB

Time

-1dB
D00AU1170

Note:

For steps more than 0.5dB the Soft Step mode should be deactivated because it could generate a hard 1dB step during the blend time.

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TDA7402

Audioprocessor part

3.7

Bass
There are four parameters programmable in the bass stage:

3.7.1

Attenuation
Figure 9 shows the attenuation as a function of frequency at a center frequency of 80Hz. Figure 9. Bass control @ fC = 80Hz, Q = 1
1 5 .0

1 0 .0

5 .0

dB
0 .0

- 5. 0

- 1 0. 0

- 1 5. 0 1 0 .0 1 00 . 0

Hz

1 .0 K

10 . 0 K

3.7.2

Center frequency
Figure 10 shows the eight possible center frequencies 60, 70, 80, 90, 100, 130, 150 and 200Hz. Figure 10. Bass center frequencies @ gain = 14dB, Q = 1
15.0

12.5

10.0

7. 5

dB
5. 0

2. 5

0. 0 10.0 100.0 1.0K 10.0K

Hz

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Audioprocessor part

TDA7402

3.7.3

Quality factors
Figure 11 shows the four possible quality factors 1, 1.25, 1.5 and 2. Figure 11. Bass quality factors @ Gain = 14dB, fC = 80Hz
15.0

12.5

10.0

7.5

5.0

2.5

0.0

10.0

100.0

1.0K

10.0K

3.7.4

DC mode
In this mode the DC-gain is increased by 4.4dB. In addition the programmed center frequency and quality factor is decreased by 25% which can be used to reach alternative center frequencies or quality factors. Figure 12. Bass normal and DC Mode @ Gain = 14dB, fC = 80Hz
15.0

12.5

10.0

7.5

5.0

2.5

0.0 10.0 100.0 1.0K 10.0K

Note:

The center frequency, Q and DC-mode can be set fully independently.

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TDA7402

Audioprocessor part

3.8

Treble
There are two parameters programmable in the treble stage:

3.8.1

Attenuation
Figure 13. shows the attenuation as a function of frequency at a center frequency of 17.5kHz. Figure 13. Treble control @ fC = 17.5kHz
15.0

10.0

5.0

0.0

-5.0

-10.0

-15.0 10.0 100.0 1.0K 10.0K

3.8.2

Center frequency
Figure 14. shows the four possible center frequencies 10k, 12.5k, 15k and 17.5kHz. Figure 14. Treble center frequencies @ gain = 14dB
15.0

12.5

10.0

7.5

5.0

2.5

0.0 10.0 100.0 1.0K 10.0K

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TDA7402

3.9

Subwoofer application
Figure 15. Subwoofer application with LPF 80/120/160Hz and HPF 90/135/180Hz

0.0

-10.0

-20.0

dB
-30.0

-40.0

-50.0 10.0

100.0

Hz

1.0K

10.0K

Both filters, the lowpass and the highpass-filter, have butterworth characteristics so that their cut off frequencies are not equal, but shifted by the factor 1.125 to get a flat frequency response.

3.10

Voice band application
Figure 16. Voiceband application with HPF 300/450/600/750Hz and LPF 3k/6kHz

0.0

-10.0

-20.0

dB
-30.0

-40.0

-50.0 10.0

100.0

Hz

1.0K

10.0K

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TDA7402

Audioprocessor part

3.11

Compander
Signal compression A fully integrated signal compressor with programmable attack and decay times is present in the TDA7402 (see Figure 17). The compander consists of a signal level detection, an A/D Converter plus adder and the normal Soft Step volume stage. First of all the left and the right InGain-signal is rectified, respectively, and the logarithm is build from the summed signal. The following low-pass smooth the output-signal of the logarithm amplifier and improves the low frequency suppression. The low pass output-voltage then is A/D converted an added to the current volume-word defined by the I2C bus. Assuming reference level or higher at the compander input, the output of the ADC is 0. At lower levels the voltage is increasing with 1Bit/dB. It is obvious that with this configuration and a 0.5dB-step volume stage the compression rate is fixed to 2:1 (1dB less at the input leads to 0.5dB less at the output). The internal reference level of the compander is programmable in three steps from 0.5VRMS to 2VRMS. For a proper behavior of the compression circuit it is mandatory to have at a 0dB input signal exactly the programmed reference level after the InGain-stage. E.g. at a configured reference-level of 0.5VRMS the output of the InGain stage has to have also 0.5VRMS at 0dB source-signal (Usually the 0dB for CD is defined as the maximum possible signal-level). To adapt the external level to the internal reference level the programmable attenuation in the differential stages and the InGain can be used. Figure 17. Compander block diagram
SOFT STEP VOLUME
INL INR INL INR OUTL OUTR OUTL OUTR

8 Bit IIC-BUS VOLUME CONTROL 8 Bit

6 Bit

ADDER
CLKATT CLKREL D A

LIN

STEREO FULL WAVE RECTIFIER

50Hz LOW-PASS

ANTI-CLIP ENABLE AM MPIN INPUT SELECT

RIN

+

LOG AMPL

+

CLPIN

D00AU1147

3.11.1

Anti-clipping
In a second application the compander-circuit can be used for a anti-clipping or limiting function. In this case one of the dedicated inputs (AM or MPin) is connected directly to the clip-detector of the power-amplifier. if no clipping is detected, the open-collector output of the power-amplifier is highohmic and the input-voltage of the rectifier is VREF. The level detector interprets this as a very small signal and reacts with the maximum programmed compander gain. In the application this gain has to be compensated by decreasing the

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Audioprocessor part

TDA7402

volume with the same value in order to get the desired output-level. In clipping situation the open collector current generates a voltage drop at the rectifier input, which forces the compander to decrease the gain until the clipping disappears. It is even possible to run the compression mode and the anti-clipping mode in parallel. In this case the maximum compander gain should be set to 29dB.

3.11.2

Characteristic
To achieve the desired compression characteristic like shown below the volume has to be decreased by 4dB. Figure 18. Compander characteristic
0 -8dB 2:1 -20 -38dB -30 15dB

-10

Output Level dB

-40

-50

-60 0 -10 -20 -30 -40 -50 -60

Input Level

dB

3.11.3

I2C bus timing
While the compander is working, a volume word coming from this stage is added to the I2C bus volume word, and the volume is changed with a soft slope between adjacent steps (Soft Step stage). As mentioned in the description of this stage, it is not recommended to change the volume during this slope. To avoid this while the compander is working and the volume has to be changed, the compander hold-bit is implemented (Bit 7 in the subaddress byte). The recommended timing for changing the volume during compander ON is the following: 1. 2. 3. 4. Set the compander hold bit Wait the actual Soft Step time Change the volume Reset the compander hold bit

The Soft Step times are in compander ON condition automatically adapted to the attack time of the compander. In the following table the related Soft Step times are shown: Table 6. Attack times vs. soft-step times
Attack time 6ms 12ms 24ms 48ms Soft Step time 0.16ms 0.32ms 0.64ms 1.28ms

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TDA7402

Audioprocessor part

3.12

AC coupling
In some applications additional signal manipulations are desired, for example surround sound or more band equalizing. For this purpose an AC coupling is placed before the speaker attenuator, which can be activated or internally shorted by the I2C bus. In short condition the input signal of the speaker attenuator is available at the AC outputs. The input impedance of this AC Inputs is 50k.

3.13

Output selector
The output-selector allows to connect the main- or the second-source to the front, rear and subwoofer speaker attenuator, respectively. As an example of this programming the device is able to connect via software the main source to the back (rear) and the second source to the front (see Figure 17). In addition to this stage allows to setup different applications by I2C bus programming. Three examples are given in Figure 18, 19, and 20. Figure 19. Output selector
ACOUT ACINF ACINR SWIN

MAIN SOURCE LEFT CHANNEL

VOICE BAND BANDPASS

SPEAKER FRONT

SPEAKER REAR

25K MS MONO MAIN SOURCE 25K RIGHT CHANNEL

50K

50K

50K

LOWPASS SECOND SOURCE 25K SEC.S MONO 25K LEFT CHANNEL SECOND SOURCE
D00AU1155

SPEAKER SUBWOOFER

OFF/ON FC

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Audioprocessor part

TDA7402

3.14

Subwoofer
Several different applications are possible with the subwoofer circuit: 1. Subwoofer filter OFF a) b) c) d) 2. a) b) c) Main source stereo (AC coupled) Second source stereo (DC coupled) Main source mono differential (DC coupled) Second source mono-differential (DC coupled) Main source mono differential (DC coupled) Second source mono differential (DC coupled) Center speaker mode (filtered mono signal at SWL, unfiltered mono signal at SWR)

Subwoofer filter ON

In all applications the phase of the output-signal can be configured to be 0 or 180. In the center speaker mode only at the filtered output the phase is changed. Figure 20. Application 1 using internal highpass and mono low pass filter
PROGRAMMING 5/1xxxxxxx 7/xxxxx1xx 10/xxxx10xx 12/1010xxxx ACINF 220nF 220nF

ACOUT

ACINR

SWIN

MAIN SOURCE BASS-FILTER LEFT CHANNEL

VOICE BAND BANDPASS

SPEAKER FRONT

SPEAKER REAR

25K MS MONO MAIN SOURCE RIGHT CHANNEL 25K

50K

50K

50K

LOWPASS SECOND SOURCE 25K SEC.S MONO 25K LEFT CHANNEL OFF/ON FC

SPEAKER SUBWOOFER

D00AU1156

SECOND SOURCE

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TDA7402

Audioprocessor part Figure 21. Application 2 using internal highpass and external stereo low pass filter
PROGRAMMING 5/0xxxxxxx 7/xxxxx1xx 10/xxxx11xx 12/1010xxxx ACINF ACOUT EXTERNAL LOWPASS 220nF

ACINR

SWIN

MAIN SOURCE BASS-FILTER LEFT CHANNEL

VOICE BAND BANDPASS

SPEAKER FRONT

SPEAKER REAR

25K MS MONO MAIN SOURCE RIGHT CHANNEL 25K

50K

50K

50K

LOWPASS SECOND SOURCE 25K SEC.S MONO 25K LEFT CHANNEL OFF/ON FC

SPEAKER SUBWOOFER

D00AU1157

SECOND SOURCE

Figure 22. Application 3 using pure external filtering (e.g. DSP)
PROGRAMMING 5/1xxxxxxx 7/xxxxx0xx 10/xxxx11xx 12/1010xxxx EXTERNAL FILTERING

220nF ACINF

220nF ACOUT

220nF ACINR

220nF SWIN

MAIN SOURCE BASS-FILTER LEFT CHANNEL

VOICE BAND BANDPASS

SPEAKER FRONT

SPEAKER REAR

25K MS MONO MAIN SOURCE RIGHT CHANNEL 25K

50K

50K

50K

LOWPASS SECOND SOURCE 25K SEC.S MONO 25K LEFT CHANNEL OFF/ON FC

SPEAKER SUBWOOFER

D00AU1163

SECOND SOURCE

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Audioprocessor part

TDA7402

3.15

Speaker attenuator and mixing
A mixing-stage is placed after each speaker attenuator and can be set independently to mixing mode. Having a full volume for the mix signal the stage offers a wide flexibility to adapt the mixing levels. Figure 23. Output selector

FRONT

VOLUME +15/-79dB 1dB Step

1 25K

OUTF

FROM OUTPUT SELECTOR REAR VOLUME +15/-79dB 1dB Step

1 25K

OUTR

FROM MIXING SELECTOR

VOLUME +15/-79dB 1dB Step

25K

25K

D00AU1164

3.16

Audioprocessor testing
During the testmode, which can be activated by setting bit D0 of the stereo decoder testing byte and the audioprocessor testing byte, several internal signals are available at the FD2R pin. During this mode the input resistance of 100kOhm is disconnected from the pin. The internal signals available are shown in the data byte specification.

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TDA7402

Stereo decoder part

4
4.1

Stereo decoder part
Stereo decoder part features

No external components necessary PLL with adjustment free, fully integrated VCO Automatic pilot dependent MONO/STEREO switching Very high suppression of intermodulation and interference Programmable roll off compensation Dedicated RDS-Soft Mute Highcut and stereo blend-characteristics programmable in a wide range FM/AM noiseblanker with several threshold controls Multipath-detector with programmable internal/external influence I2C-bus control of all necessary functions

4.2

Stereo decoder electrical characteristics
VS = 9V, de-emphasis time constant = 50s, MPX input voltage VMPX = 500mV (75kHz deviation), modulation frequency = 1kHz, input gain = 6dB, Tamb = 27C, unless otherwise specified.

Table 7.
Symbol Vin R in G min Gmax Gstep SVRR a THD
S+N N

Stereo decoder electrical characteristics
Parameter MPX input level Input resistance Min. input gain Max. input gain Step resolution Supply voltage ripple rejection Max. channel separation Total harmonic distortion Signal plus noise to noise ratio fin=1kHz, mono A-weighted, S = 2Vrms 80 Vripple = 100mV, f = 1kHz 30 Test condition Input gain = 3.5dB 70 1.5 8.5 1.75 Min. Typ. 0.5 100 3.5 11 2.5 55 50 0.02 91 0.3 Max. 1.25 130 4.5 12.5 3.25 Unit Vrms k dB dB dB dB dB % dB

Mono/Stereo-switch VPTHST1 VPTHST0 VPTHMO1 VPTHMO0 PLL f/f Capture range 0.5 % Pilot threshold voltage Pilot threshold voltage Pilot threshold voltage Pilot threshold voltage for stereo, PTH = 1 for stereo, PTH = 0 for mono, PTH = 1 for mono, PTH = 0 10 15 7 10 15 25 12 19 25 35 17 25 mV mV mV mV

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Stereo decoder part Table 7.
Symbol

TDA7402

Stereo decoder electrical characteristics (continued)
Parameter Test condition Min. Typ. Max. Unit

De-emphasis and highcut VLEVEL >> VHCH DeempFM De-emphasis time constants FM VLEVEL >> VHCH VLEVEL >> VHCH VLEVEL >> VHCH MFM Highcut time constant multiplier FM VLEVEL << VHCL VLEVEL >> VHCH DeempAM De-emphasis time constants AM VLEVEL >> VHCH VLEVEL >> VHCH VLEVEL >> VHCH MAM REF5V Lmin Lmaxs LGstep VSBLmin VSBLmax VSBLstep Highcut time constant multiplier AM Internal reference voltage min. LEVEL gain max. LEVEL gain LEVEL gain step resolution Min. voltage for mono Max. voltage for mono Step resolution see section 2.7 see section 2.8 see section 2.8 see section 2.8 see section 2.9 see section 2.9 see section 2.9 see section 2.9 see section 2.9 see section 2.9 VLEVEL << VHCL 4.7 -1 5 0.2 17 62 1.6 37 58 4.2
15 29

25 44 50 70

50 62.5 75 100 3 37.5 47 56 75 3.7 5 0 6 0.4 20 70 3.3 42 66 8.4
17 33

75 80 100 130

s s s s

s s s s

5.3 1 7 0.6 23 78 5.0 47 74 12.6
19 37

V dB dB dB %REF 5V %REF 5V %REF 5V %REF 5V %REF 5V %REF 5V
%VHCH %VHCH

VHCHmin Min. voltage for NO highcut VHCHmax Max. voltage for NO highcut VHCHstep Step resolution VHCLmin Min. voltage for FULL high cut

VHCLmax Max. voltage for FULL high cut VHCLstep Step resolution

2.1

4.2

6.3

%REF 5V

Carrier and harmonic suppression at the output 19 38 57 76 Pilot signal f=19kHz Subcarrier f=38kHz Subcarrier f=57kHz Subcarrier f=76kHz 40 50 75 62 90 dB dB dB dB

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TDA7402 Table 7.
Symbol

Stereo decoder part Stereo decoder electrical characteristics (continued)
Parameter Test condition Min. Typ. Max. Unit

Intermodulation (Note 4.3.1) 2 3 fmod=10kHz, fspur=1kHz fmod=13kHz, fspur=1kHz 65 75 dB dB

Traffic Radio (Note 4.3.2) 57 Signal f=57kHz 70 dB

SCA - Subsidiary Communications Authorization (Note 4.3.3) 67 Signal f = 67kHz 75 dB

ACI - Adjacent Channel Interference (Note 4.3.4) 114 190 Signal f=114kHz Signal f=190kHz 95 84 dB dB

4.3
4.3.1

Notes about the characteristics
Intermodulation suppression
V O ( s i g n a l ) ( a t 1 k Hz ) 2 = -------------------------------------------------------------- ;f s = ( 2 10 k H z ) 19 k H z V O ( s p u r i o u s ) ( a t 1 k Hz ) V O ( s i g n a l ) ( a t 1 k Hz ) 3 = -------------------------------------------------------------- ;f s = ( 3 13 k H z ) 38 k H z V O ( s p u r i o u s ) ( a t 1 k Hz ) measured with: 91% pilot signal; fm = 10kHz or 13kHz.

4.3.2

Traffic radio (V.F.) suppression
V O ( s i g n a l ) ( a t 1 kHz ) 57 ( V .W .F ) = --------------------------------------------------------------------------------------V O ( s p u r i o u s ) ( a t 1 k Hz 2 3 k H z ) measured with: 91% stereo signal; 9% pilot signal; fm=1kHz; 5% subcarrier (f=57kHz, fm=23Hz AM, m=60%)

4.3.3

SCA (subsidiary communications authorization)
V O ( s i g n a l ) ( a t 1 kHz ) 67 = -------------------------------------------------------------- ;f s = ( 2 38 k H z ) 67 k H z V O ( s p u r i o u s ) ( a t 1 kHz ) measured with: 81% mono signal; 9% pilot signal; fm=1kHz; 10%SCA - subcarrier (fS = 67kHz, unmodulated).

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Stereo decoder part

TDA7402

4.3.4

ACI (adjacent channel interference)
V O ( s i g n a l ) ( a t 1 kHz ) 114 = -------------------------------------------------------------- ;f s = 110 k H z ( 3 38 k H z ) V O ( s p u r i o u s ) ( a t 4 kHz ) V O ( s i g n a l ) ( a t 1 kHz ) 190 = -------------------------------------------------------------- ;f s = 186 k H z ( 5 38 k H z ) V O ( s p u r i o u s ) ( a t 4 kHz ) measured with: 90% mono signal; 9% pilot signal; fm=1kHz; 1% spurious signal (fS = 110kHz or 186kHz, unmodulated).

4.4
4.4.1

Noise blanker part
Noise blanker part features

AM and FM mode internal 2nd order 140kHz high-pass filter for MPX path internal rectifier and filters for AM-IF path programmable trigger thresholds trigger threshold dependent on high frequency noise with programmable gain additional circuits for deviation and fieldstrength dependent trigger adjustment 4 selectable pulse suppression times for each mode programmable noise rectifier charge/discharge current

All parameters measured in FM mode if not otherwise specified. Table 8.
Symbol

Noise blanker electrical characteristics
Parameter Test condition 111 110 101 Min. Typ. 30 35 40 45 50 55 60 65 260 220 180 140 Max. Unit mVOP mVOP mVOP mVOP mVOP mVOP mVOP mVOP mVOP mVOP mVOP mVOP

VTR

Trigger threshold (1)

meas.with VPEAK=0.9V

100 011 010 001 000 00

VTRNOISE

Noise controlled Trigger threshold

meas.with VPEAK=1.5V

01 10 11

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TDA7402 Table 8.
Symbol

Stereo decoder part Noise blanker electrical characteristics (continued)
Parameter Test condition VMPX=0mV Min. 0.5 1.5 2 11 10 01 00 11 10 01 00 00 01 10 11 00 01 10 11 00 01 10 11 0 1 00 01 10 11 35 Signal AM-RECTIFIER in Testmode 0.5 0.9 1.7 2.5 0.5 0.9 1.7 2.1 Typ. 0.9 1.7 2.5 0.9(off) 1.2 2.0 2.8 0.9(off) 1.4 1.9 2.4 38 25.5 32 22 1.2 800 1.0 640 0.3 0.8 1.3 2.0 10 20 0.3 0.5 0.7 0.9 50 6 20 2 Signal AM-RECTIFIER in Testmode 14 56 65 Max. 1.3 2.1 2.9 1.3 1.5 2.3 3.1 1.3 1.5 2.3 3.1 Unit V V V VOP VOP VOP VOP V V V V s s s s ms s s s

VRECT

Rectifier voltage

VMPX=50mV, f=150kHz VMPX=200mV, f=150kHz

VRECTDE Deviation dependent rectifier voltage V

meas.with VMPX=500mV (75kHz dev.) meas.with VMPX=0mV, VLEVEL<< VSBL (fully mono)

Fieldstrength VRECTFS controlled rectifier voltage

TSFM

Suppression pulse duration FM

Signal HOLDN in testmode

TSAM

Suppression pulse duration AM

Signal HOLDN in testmode

VRECTAD Noise rectifier discharge adjustment J Noise rectifier (2) charge

(2)

Signal PEAK in testmode

V/ms

SRPEAK

Signal PEAK in testmode

mV/s

VADJMP

Noise rectifier adjustment through multipath (2)

Signal PEAK in testmode

V/ms

RAMIF

AM IF Input resistance

kOhm dB dB dB kHz kHz

GAMIF,min min. gain AM IF GAMIF,max max. gain AM IF GAMIF,step step gain AM IF fAMIF,min min. fc AM IF fAMIF,max max. fc AM IF

1. All thresholds are measured using a pulse with TR = 2 s, THIGH= 2 s and TF = 10 s. The repetition rate must not increase the PEAK voltage. 2. By design/characterization functionally guaranteed through dedicated test mode structure

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Stereo decoder part Figure 24. Vn timing diagram
V in
V op

TDA7402

DC

T im e TR T HIGH T F

Figure 25. Trigger threshold vs. VPEAK
V TH

2 6 0 m V (00) 2 2 0 m V (01) 1 8 0 m V (10) 1 4 0 m V (11)

M I N . TR IG . T H R E S H O L D

N O IS E C O N T R O L L E D T R IG . TH R E S H O L D

65 m V 8 STEPS 30 m V

0 .9 V

1 .5 V

V P E A K [V ]

Figure 26. Deviation controlled trigger adjustment
VP E A K
[V
OP

]

00 2 .8 01 2 .0 10 1 .2 0 .9 D e te c to r o ff (11)

20

3 2 .5

45

75

D E V IA T I O N [KH z ]

Figure 27. Field strength controlled trigger adjustment
VPEAK

MONO

STERE O

» 3V

2.3V (00) 1.8V (01) 1.3V (10) NOIS E ATC_SB OFF (11) 0.9V

noisy signal

good signal

E'

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TDA7402

Stereo decoder part

4.5
4.5.1

Multipath detector
Multipath detector features

internal 19kHz band pass filter programmable band pass and rectifier gain selectable internal influence on stereo blend and/or Highcut Multipath detector electrical characteristics
Parameter Center frequency of multipath-bandpass Test Condition Stereo decoder locked on pilot tone G1 G2 GBPMP Bandpass gain G3 G4 G1 16 18 7.6 4.6 0 0.25 0.5 4 dB dB dB dB dB A mA Min. Typ. 19 6 12 Max. Unit kHz dB dB

Table 9.
Symbol fCMP

GRECTM
P

Rectifier gain

G2 G3

ICHMP IDISMP

Rectifier charge current Rectifier discharge current

Quality detector 00 01 10 11 0.70 0.85 1.00 1.15

A

Multipath influence factor

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Functional description of stereo decoder

TDA7402

5

Functional description of stereo decoder

Figure 28. Block diagram of stereo decoder
DEMODULATOR MPX 100K INGAIN 3.5 ... 11dB STEP 2.5dB INFILTER LP 80KHz 4.th ORDER - PLOT CANC - ROLL-OFF COMP. - LP 25KHz DEEMPHASIS + HIGHCUT t=50.62..5.75,100s (37.5,47,56,75s) FM_L

FM_R

AM 100K PLL + PILOT-DET. F19 F38 STEREO MPSBINFL SB CONTROL

5 bits HC CONTROL D A

REF 5V VSBL

VHCCH VHCCL

NOISE BLANKER HOLDN AM-IF NOISE

MPHCINFL MULTIPATH DET. MPHCOUT MPSBOUT

LEVELSB-LP LEVEL INPUT GAIN 0..6dB LEVEL

-

LEVELHC-LP

QUALITY DETECTOR +
D00AU1135

QUAL

MP-IN

MP-OUT

The stereo decoder-part of the TDA7402 (see Figure 28) contains all functions necessary to demodulate the MPX-signal like pilot tone dependent Mono/Stereo switching as well as "stereo blend" and "highcut". Adaptations like programmable input gain, roll off compensation, selectable de-emphasis time constant and a programmable fieldstrength input allow to use different IF devices.

5.1

Stereo decoder mute
The TDA7402 has a fast and easy to control RDS mute function which is a combination of the audioprocessor's Soft Mute and the high ohmic mute of the stereo decoder. If the stereo decoder is selected and a Soft Mute command is sent (or activated through the SM-pin) the stereo decoder will be set automatically to the high-ohmic mute condition after the audiosignal has been softmuted. Hence a checking of alternate frequencies could be performed. Additionally the PLL can be set to "Hold" mode, which disables the PLL input during the mute time. To release the system from the mute condition simply the unmute command must be sent: the stereo decoder is unmuted immediately and the audioprocessor is softly unmuted. Figure 29 shows the output-signal VO as well as the internal stereo decoder mute signal. This influence of Soft Mute on the stereo decoder mute can be switched off by setting bit 3 of the Soft Mute byte to "0". A stereo decoder mute command (bit 0, stereo decoder byte set to "1") will also set the stereo decoder independently to the high-ohmic mute state. If any other source than the stereo decoder is selected the decoder remains muted and the MPX pin is connected to Vref to avoid any discharge of the coupling capacitor through leakage currents. No further mute command should be applied.

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TDA7402

Functional description of stereo decoder Figure 29. Signals during stereo decoder's Soft Mute

Figure 30. Signal control via Soft Mute pin
PLL-HOLD INFLUENCE SOFTMUTE INFLUENCE STDHMUTE INFLUENCE STDHMUTE SOFTMUTE INFLUENCE SOFTMUTE PIN IIC-BUS SOFTMUTE MP-HOLD PLL-HOLD

MUTED

D00AU1165

5.2

InGain + infilter
The InGain stage allows adjustment of the MPX-signal to a magnitude of about 1Vrms internally, which is the recommended value. The 4th order input filter has a corner frequency of 80kHz and is used to attenuate spikes and noise, and acts as an anti-aliasing filter for the following switch capacitor filters.

5.3

Demodulator
In the demodulator block, the left and the right channels are separated from the MPX signal. In this stage the 19kHz pilot tone is cancelled. To reach a high channel separation the TDA7402 offers an I2C bus programmable roll-off adjustment which is able to compensate for the lowpass behavior of the tuner section. If the tuner's attenuation at 38kHz is in a range from 7.2% to 31.0%, the TDA7402 needs no external network in front of the MPX-pin. Within this range, an adjustment to obtain at least 40dB channel separation is possible. The bits for this adjustment are located together with the fieldstrength adjustment in one byte. This gives the possibility to perform an optimization step during the production of the car radio, where

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Functional description of stereo decoder

TDA7402

the channel separation and the fieldstrength control are trimmed. The setup of the stereo blend characteristics which is programmable in a wide range is described in Chapter 5.8.

5.4

De-emphasis and highcut
The de-emphasis lowpass allows to choose a time constant between 37.5 and 100s. The highcut control range will be 2 x Deemp or 2.7 x Deemp dependent on the selected time constant (see programming section). The bit D7 of the hightcut-byte will shift timeconstant and range. Inside the highcut control range (between VHCH and VHCL) the LEVEL signal is converted into a 5 bit word which controls the lowpass time constant between Deemp...3 (3.7) x Deemp. Thereby the resolution will remain always 5 bits independently of the absolute voltage range between the VHCH and VHCL values. In addition the maximum attenuation can be fixed between 2 and 10dB. The highcut function can be switched off by I2C bus (bit D7, Highcut byte set to "0"). The setup of the highcut characteristics is described in Chapter 5.9.

5.5

PLL and pilot tone detector
The PLL has the task to lock on the 19kHz pilot tone during a stereo transmission to allow a correct demodulation. The included pilot tone-detector enables the demodulation if the pilot tone reaches the selected pilot tone threshold VPTHST. Two different thresholds are available. The detector output (signal STEREO, see Figure 2: Block diagram) can be checked by reading the status byte of the TDA7402 via I2C-bus. During a Soft Mute the PLL can be set into "Hold"-mode which freezes the PLL's state (bit D4, Soft Mute byte). After releasing the Soft Mute the PLL will again follow the input signal only by correcting the phase error.

5.6

Fieldstrength control
The fieldstrength input is used to control the highcut and the stereo blend function. In addition the signal can be also used to control the noiseblanker thresholds and as input for the multipath detector. These additional functions are described in sections 5.3 and 6.

5.7

EVEL input and gain
To suppress undesired high frequency modulation on the highcut- and stereo blend-control signal the LEVEL signal is lowpass filtered firstly. The filter is a combination of a 1st order RC lowpass at 53kHz (working as anti-aliasing filter) and a 1st-order switched capacitor lowpass at 2.2kHz. The second stage is a programmable gain stage to adapt the LEVEL signal internally to different IF devices (see Testmode section 5: LEVELHCC). The gain is widely programmable in 16 steps from 0dB to 6dB (step=0.4dB). These 4 bits are located together with the Roll-Off bits in the "Stereo decoder adjustment" byte to simplify a possible adjustment during the production of the car radio. This signal controls directly the Highcut stage whereas the signal is filtered again (fc=100Hz) before the stereo blend stage (see Figure 35).

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TDA7402

Functional description of stereo decoder

5.8

Stereo blend control
The stereo blend control block converts the internal LEVEL voltage (LEVELSB) into an demodulator compatible analog signal which is used to control the channel separation between 0dB and the maximum separation. Internally this control range has a fixed upper limit which is the internal reference voltage REF5V. The lower limit can be programmed between 20 and 70% of REF5V in 3.3% steps (see Figure 31 and 32). To adjust the external LEVEL voltage to the internal range two values must be defined: the LEVEL gain LG and VSBL (see Figure 32). At the point of full channel separation the external level signal has to be amplified that internally it becomes equal to REF5V. The second point (e.g. 10dB channel sep.) is then adjusted with the VSBL voltage. Figure 31. Internal stereo blend characteristics

The gain can be programmed through 4 bits in the "Stereo decoder adjustment" byte. All necessary internal reference voltages like REF5V are derived from a bandgap circuit. Therefore they have a temperature co-efficient near zero. Figure 32. Relation between internal and external LEVEL voltages for setup of stereo blend
INTERNAL VOLTAGES REF 5V SETUP OF VST LEVEL INTERN REF 5V INTERNAL VOLTAGES SETUP OF VMO LEVEL INTERN

LEVEL VSBL VSBL

70% 20%

VMO

VST

t FIELDSTRENGHT VOLTAGE
D00AU1168

VMO

VST

t FIELDSTRENGHT VOLTAGE

5.9

Highcut control
The highcut control set-up is similar to the stereo blend control set up: the starting point VHCH can be set with 2 bits to be 42, 50, 58 or 66% of REF5V whereas the range can be set to be 17, 22, 28 or 33% of VHCH (see Figure 33).

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Functional description of stereo decoder Figure 33. Highcut characteristics
LOWPASS TIME CONSTANT

TDA7402

3.7·'Deemp 3·Deemp

DEEMPHASIS SHIFT ON

OFF

Deemp 'Deemp
VHCL
D00AU1169

VHCH FIELDSTRENGHT

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TDA7402

Functional description of the noise blanker

6

Functional description of the noise blanker
In the automotive environment the MPX-signal as well as the AM signal is disturbed by spikes produced by the ignition and other radiating sources like the wiper motor. The aim of the noiseblanker part is to cancel the audible influence of the spikes. Therefore the output of the stereo decoder is held at the actual voltage for a time between 22 and 38s in FM (370 and 645s in AM mode). The block diagram of the noise blanker is given in Figure 34. Figure 34. Block diagram of the noise blanker
AM/FM RECTIFIER + 14-56KHz LPF (1st. order) 140KHz HPF (1st. order)

AMIF

RECTIFIER

RECT

+ VTH

MONOFLOP FM: 22 to 40s AM: 370 to 6400s

HOLDN

MPX

140KHz HPF (2nd. order) INTEGRATOR

+

PEAK +

THRESHOLD GENERATOR

MPOUT

DISCHARGE CONTROL
D00AU1132

ADDITIONAL THRESHOLD CONTROL

In a first stage the spikes must be detected but to avoid a wrong triggering on high frequency (white) noise a complex trigger control is implemented. Behind the trigger stage a pulse former generates the "blanking"pulse.

6.1

Trigger path FM
The incoming MPX signal is highpass-filtered, amplified and rectified. This second order highpass filter has a corner-frequency of 140kHz. The rectified signal, RECT, is integrated (lowpass filtered) to generate a signal called PEAK. The DC-charge/discharge behavior can be adjusted as well as the transient behavior (MP discharge control). Also noise with a frequency 140kHz increases the PEAK voltage. The PEAK voltage is fed to a threshold generator, which adds to the PEAK voltage a DC dependent threshold VTH. Both signals, RECT and PEAK+VTH are fed to a comparator which triggers a re-triggerable monoflop. The monoflop's output activates the sample and hold circuits in the signalpath for the selected duration.

6.2

Noise controlled threshold adjustment (NCT)
There are mainly two independent possibilities for programming the trigger threshold: 1. 2. the low threshold in 8 steps (bits D1 to D3 of the noiseblanker byte I) and the noise adjusted threshold in 4 steps (bits D4 and D5 of the noiseblanker byte I, see Figure 21).

The low threshold is active in combination with a good MPX signal without noise; the PEAK voltage is less than 1V. The sensitivity in this operation is high. If the MPX signal is noisy (low fieldstrength) the PEAK voltage increases due to the higher noise, which is also rectified. With increasing of the PEAK voltage the trigger threshold increases, too. This gain is programmable in 4 steps (see Figure 25).

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Functional description of the noise blanker

TDA7402

6.3
6.3.1

Additional threshold control mechanism
Automatic threshold control by the stereo blend voltage
Besides the noise controlled threshold adjustment there is an additional possibility for influencing the trigger threshold which depends on the stereo blend control. The point where the MPX signal starts to become noisy is fixed by the RF part. Therefore also the starting point of the normal noise-controlled trigger adjustment is fixed (Figure 27). In some cases the behavior of the noiseblanker can be improved by increasing the threshold even in a region of higher fieldstrength. Sometimes a wrong triggering occurs for the MPX signal often shows distortion in this range which can be avoided even if using a low threshold. Because of the overlap of this range and the range of the stereo/mono transition it can be controlled by stereo blend. This increase of the threshold is programmable in 3 steps or switched off.

6.3.2

Over deviation detector
If the system is tuned to stations with a high deviation the noiseblanker can trigger on the higher frequencies of the modulation or distortion. To avoid this behavior, which causes audible noise in the output signal, the noiseblanker offers a deviation-dependent threshold adjustment. By rectifying the MPX signal a further signal representing the actual deviation is obtained. It is used to increase the PEAK voltage. Offset and gain of this circuit are programmable in 3 steps with the bits D6 and D7 of the noiseblanker byte I (bit combination '00' turns off the detector, see Figure 26).

6.3.3

Multipath level
To react on high repetitive spikes caused by a multipath-situation, the discharge time of the PEAK voltage can be decreased depending on the voltage-level at pin MPout. The TDA7402 offers a linear as well as a threshold driven control. The linear influence of the multipath level on the PEAK-signal (D7 of multipath control byte) gives a discharge slew rate of 1V/ms(a). The second possibility is to activate the threshold driven discharge which switches on the 18kOhm discharge if the multipath level is below 2.5V (D7 of noiseblanker byte II byte).

6.3.4

AM mode of the noiseblanker
The TDA7402 noiseblanker is also suitable for AM noise cancelling. The detector uses in AM mode the 450kHz unfiltered IF output of the tuner for spike detection. A combination of programmable gain stage and lowpass filter forms an envelope detector which drives the noiseblanker's input via a 120kHz 1st order highpass. In order to blank the whole spike in AM mode the hold-times of the sample and hold circuit are much longer then in FM (640s to 1.2ms). All threshold controls can be used like in FM mode.

a. The serrate is measured with RDischarge = infinite and VMPout = 2.5 V.

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TDA7402

Functional description of the multipath detector

7

Functional description of the multipath detector
Using the multipath detector the audible effects of a multipath condition can be minimized. A multipath condition is detected by rectifying the spectrum around 19kHz in the fieldstrength signal. An external capacitor is used to define the attack and decay times for the stereo blend (see block diagram, Figure 34). Due to the very small charge currents this capacitor should be a low leakage current type (e.g ceramic). Using this configuration an adaptation to the user's requirement is possible without effecting the "normal" fieldstrength input (level) for the stereo decoder. This application is given in Figure 34. Another (internal) time constant is used to control the Highcut through the multipath detector Selecting the "internal influence" in the configuration byte the stereo-blend and/or the highcut is automatically invoked during a multipath condition according to the voltage appearing at the MP_OUT pin. Figure 35. Block diagram of the multipath detector
VDD = High-Cut-Infl. Attach<500s Decay=2/10ms INT. INFLUENCE LOWPASS 100Hz LOWPASS 53KHz LOWPASS 2.2KHz VDD = SHIFT 0 ... 1.5V CHARGE 0.25A/0.5A VDD = 300A Stereoblend-Infl. FAST CHARGE Attach=1ms Decay=4/8s INT. INFLUENCE to SB

to HCC

LEVEL

MP HOLD MP_OUT MP_IN BANDPASS 19KHz RECTIFIER 470nF

GAIN 2 bits

GAIN 2 bits

D00AU1166

7.1

Quality detector
The TDA7402 offers a quality detector output which gives a voltage representing the FM reception conditions. To calculate this voltage the MPX-noise and the multipath-detector output are summed according to the following formula: VQual = 1.6 (VNoise-0.8 V)+ a (REF5V-VMpout). The noise-signal is the PEAK signal without additional influences (see the noiseblanker description). The factor 'a' can by programmed to 0.7 .... 1.15. The output is a low impedance output able to drive external circuitry as well as simply fed to an AD converter for RDS applications.

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Functional description of the multipath detector

TDA7402

7.2

Testmode
During the testmode, which can be activated by setting bit D0 and bit D1 of the stereo decoder testing byte, several internal signals are available at the FD2R+ pin. During this mode the input resistance of 100kOhm is disconnected from the pin. The internal signals available are shown in the Data byte specification.

7.3
7.3.1

Dual MPX usage
Feature description
The TDA7402 is able to support a twin tuner concept via the Dual MPX Mode. In this configuration the MPX pin and the MD2G pin are acting as MPX1 and MPX2 inputs. The DC voltage at the MD2 pin controls whether one or both MPX signals are used to decode the stereo FM signal. It is designed as a window comparator with the characteristic shown in Figure 3 (Please note that the thresholds have a hysteresis of 500mV). In this mode the stereo decoder high ohmic-mute mutes both inputs in parallel. Figure 36. Dual MPX input diagram

MPX/ MPX1 100K

1 40K INGAIN 3.5...11dB step 2.5dB

40K MD2G/ MPX2 100K MD2/ CONTROL CONTROL CIRCUITRY 1

1

D00AU1167

7.3.2

Configuration
The Dual MPX mode can be easily configured by setting bit 3 of subaddress 30 to LOW (see Byte 30 description and application diagram of Figure 38).

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TDA7402

I2C bus interface

8
8.1

I2C bus interface
Interface protocol

The interface protocol comprises: a start condition (S) a chip address byte (the LSB bit determines read / write transmission) a subaddress byte a sequence of data (N-bytes + acknowledge) a stop condition (P)
CHIP ADDRESS SUBADDRESS DATA 1....DATA n

MSB S 1 0 0 0 1 1 0

LSB R/W ACK

MSB C AZ I A A A

LSB A A ACK

MSB DATA

LSB ACK P

S = Start R/W = "0" -> Receive-Mode (Chip could be programmed by P) "1" -> Transmission-Mode (Data could be received by P) ACK = Acknowledge P = Stop Max clock speed 500kbits/s

8.2

Auto increment
If bit I in the subaddress byte is set to "1", the auto increment of the subaddress is enabled.

8.3

Transmitted data (send mode)
Table 10.
MSB X X X X X P ST

Transmitted data (send mode)
LSB SM

SM = Soft mute activated ST = Stereo P = Pause X = Not Used

The transmitted data is automatically updated after each ACK. Transmission can be repeated without new chipaddress. A Power-On-Reset is invoked if the Supply voltage is below than 3.5V. After that the following data is written automatically into the registers of all subaddresses: Table 11.
MSB 1 1 1 1 1 1 1

Reset condition
LSB 0

The programming after POR is marked bold-face / underlined in the programming tables. With this programming all the outputs are muted to VREF (VOUT= VDD/2).
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I2C bus interface

TDA7402

8.4

Subaddress (receive mode)
Table 12.
MSB I2 0 1 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 I1 I0 A4 A3 A2 A1

Subaddress (receive mode)
LSB Function A0 Compander hold off on AutoZero remain off on Auto Increment Mode off on Subaddress Main Source Selector Main Loudness Volume Treble Bass Mixing Programming Soft Mute Voice-Band Second Source Selector Second Source Loudness Subwoofer Config. / Bass Compander Configuration Audioprocessor I Configuration Audioprocessor II Subwoofer attenuator L Subwoofer attenuator R Speaker attenuator LF Speaker attenuator RF Speaker attenuator LR Speaker attenuator RR Mixing Level Control Testing Audioprocessor stereo decoder Noise-Blanker I Noise-Blanker II AM / AM-Noiseblanker High-Cut Control Fieldstr. & Quality Multipath-Detector stereo decoder Adjustment Configuration stereo decoder Testing Sterodecoder

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TDA7402

I2C bus interface

8.5

Data byte specification
The status after power on reset is marked bold face / underlined in the programming tables. Table 13.
MSB D7 D6 D5 D4 D3 D2 0 0 0 0 1 1 1 1 0 0 : 1 1 0 1 0 0 : 1 1 0 0 : 1 1 0 1 : 0 1 D1 0 0 1 1 0 0 1 1

Main selector (0)
LSB Function D0 0 1 0 1 0 1 0 1 Source selector FD1 / SE2 SE3 FD2 SE1 MD2 MD1 / SE4 Stereo decoder AM Input gain 0dB 1dB : 14dB 15dB Mute off on

Table 14.
MSB D7 D6

Main loudness (1)
LSB Function D5 D4 0 0 : 0 0 : 1 : D3 0 0 : 1 1 : 0 : D2 0 0 : 1 1 : 0 : D1 0 0 : 1 1 : 1 : D0 0 1 : 0 1 : 1 : Attenuation 0 dB -1 dB : -14 dB -15 dB : -19 dB not allowed Center frequency 200Hz 400Hz 600Hz 800Hz Loudness order First order Second order

0 0 1 1 0 1

0 1 0 1

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I2C bus interface Table 15.
MSB D7 0 0 : 0 0 0 : 0 0 0 : 1 1 D6 0 0 : 0 0 0 : 0 1 1 : 1 1 D5 0 0 : 0 0 0 : 1 0 0 : 0 0 D4 0 0 : 1 1 1 : 1 0 0 : 1 1 D3 0 0 : 1 1 1 : 1 0 0 : 1 1 D2 0 0 : 0 0 0 : 1 0 0 : 1 1 D1 0 0 : 0 0 1 : 1 0 0 : 1 1

TDA7402 Volume (2)
LSB Attenuation D0 0 1 : 0 1 0 : 1 0 1 : 0 1 Gain/attenuation (+32.0dB) (+31.5dB) : +20.0dB +19.5dB +19.0dB : +0.5dB 0.0dB -0.5dB : -79.0dB -79.5dB

Note:

It is not recommended to use a gain more than 20dB for system performance reason. In general, the maximum gain should be limited by software to the maximum value, which is needed for the system. Table 16.
MSB D7 D6 D5 D4 0 0 : 0 0 1 1 : 1 1 0 0 1 1 0 1 0 1 0 1 D3 0 0 : 1 1 1 1 : 0 0 D2 0 0 : 1 1 1 1 : 0 0 D1 0 0 : 1 1 1 1 : 0 0

Treble filter (3)
LSB Function D0 0 1 : 0 1 1 0 : 1 0 Treble steps -15dB -14dB : -1 dB 0 dB 0 dB +1 dB : +14 dB +15dB Treble center frequency 10.0 kHz 12.5 kHz 15.0 kHz 17.5 kHz Subwoofer + center speaker mode On Off

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TDA7402 Table 17.
MSB D7 D6 D5 D4 0 0 : 0 0 1 1 : 1 1 0 0 1 1 0 1 0 1 0 1 D3 0 0 : 1 1 1 1 : 0 0 D2 0 0 : 1 1 1 1 : 0 0 D1 0 0 : 1 1 1 1 : 0 0

I2C bus interface Bass filter (4)
LSB Function D0 0 1 : 0 1 1 0 : 1 0 Bass steps -15dB -14dB : -1 dB 0 dB 0 dB +1 dB : +14 dB +15dB Bass Q-factor 1.0 1.25 1.5 2.0 Bass DC-mode Off On

Table 18.
MSB D7 D6

Mixing programming (5)
LSB D5 D4 D3 D2 D1 D0 0 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 Function Mixing Mute enable Mixing source Beep MD1 MD2 FM mono Mixing target Speaker LF off Speaker LF on Speaker RF off Speaker RF on Speaker LR off Speaker LR on Speaker RR off Speaker RR on Stereo subw. using internal highpass filter On Off

0 1 0 1

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I2C bus interface Table 19.
MSB D7 D6 D5 D4 D3 D2 D1

TDA7402 Soft mute (6)
LSB Function D0 0 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 Soft Mute On (Mute) Off Mutetime = 0.48ms Mutetime = 0.96ms Mutetime = 123ms Mutetime = 324 ms Influence on stereo decoder highohmic mute on off Influence on pilot detector hold and MP hold on off Influence on Soft Mute on off Beep frequencies 600 Hz 780 Hz 1.56 kHz 2.4 kHz

0 0 1 1

0 1 0 1

Table 20.
MSB D7 D6

Voiceband (7)
LSB Function D5 D4 D3 D2 D1 D0 0 1 0 1 0 1 Voice band low pass enable Filter off Filter on Voice band low pass frequency 3 kHz 6 kHz Voice band high pass enable Filter off Filter on

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TDA7402 Table 20.
MSB D7 D6 D5 0 0 0 1 1 1 1 1 0 1 0 1 D4 0 0 1 1 0 0 1 1 D3 0 1 0 1 0 1 0 1 D2 D1

I2C bus interface Voiceband (7) (continued)
LSB Function D0 High pass cut off frequency 90Hz 135Hz 180Hz 215Hz 300Hz 450Hz 600Hz 750Hz Anti clipping enable on off Anti clipping input MP-In AM

Table 21.
MSB D7 D6

Second source selector (8)
LSB Function D5 D4 D3 D2 0 0 0 0 1 1 1 1 D1 0 0 1 1 0 0 1 1 D0 0 1 0 1 0 1 0 1 Source selector FD1 / SE2 SE3 FD2 SE1 MD2 MD1 / SE4 Stereo decoder AM Input gain 0dB 1dB : 14dB 15dB Mute off on

0 0 : 1 1 0 1

0 0 : 1 1

0 0 : 1 1

0 1 : 0 1

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I2C bus interface Table 22.
MSB D7 D6 D5 D4 0 0 : 0 0 : 1 : 0 0 1 1 0 1 0 1 0 1 D3 0 0 : 1 1 : 0 : D2 0 0 : 1 1 : 0 : D1 0 0 : 1 1 : 1 :

TDA7402 Second loudness (9)
LSB Function D0 0 1 : 0 1 : 1 : Attenuation 0 dB -1 dB : -14 dB -15 dB : -19 dB not allowed Center frequency 200Hz 400Hz 600Hz 800Hz Loudness order First order Second order

Table 23.
MSB D7 D6

Subwoofer configuration / Bass (10)
LSB Function D5 D4 D3 D2 D1 0 0 1 1 0 1 0 1 0 1 D0 0 1 0 1 Subwoofer filter off 80Hz 120Hz 160Hz Subwoofer outputs differential (mono) single ended (stereo) Subwoofer source Second source Main source Subwoofer phase 180 0 Bass center frequency 60Hz 80Hz 70Hz 90Hz 100Hz 130Hz 150Hz 200Hz

0 0 0 0 1 1 1 1

0 0 1 1 0 0 1 1

0 1 0 1 0 1 0 1

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TDA7402 Table 24.
MSB D7 D6 D5 D4 D3 D2 D1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 1 1 1 1 0 1 0 1 0 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1

I2C bus interface Compander (11)
LSB Function D0 0 1 0 1 Activity / reference level off 0.5VRMS 1VRMS 2VRMS Attack-times 6ms 12ms 24ms 49ms Release-times 390ms 780ms 1.17s 1.56s Soft Step-time1) 160s 320s 640s 1.28ms 2.56ms 5.12ms 10.2ms 20.4ms Compander max. gain 29dB 19dB

Note:

The Soft Step times are only programmable while the compander is not in use. Table 25.
MSB D7 D6 D5 D4 D3 D2 D1

Configuration audioprocessor I (12)
LSB Function D0 0 1 0 1 Compander source Main selector Second source selector Soft Step off on

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I2C bus interface Table 25.
MSB D7 D6 D5 D4 D3 D2 0 1 0 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 D1

TDA7402 Configuration audioprocessor I (12) (continued)
LSB Function D0 Main loudness flat Filter ON Second loudness flat Filter ON Front speaker not allowed Second source internal coupled Main source AC coupled Main source internal coupled Rear speaker not allowed Second source internal coupled Main source AC coupled Main source internal coupled

Table 26.
MSB D7 D6

Configuration audioprocessor II (13)
LSB Function D5 D4 D3 D2 D1 D0 0 1 0 0 1 1 0 1 0 0 1 1 0 1 0 1 0 1 0 1 Pause detector off on Pause ZC window 160mV 80mV 40mV not allowed FD1 mode single ended differential FD1 attenuation -12dB -6dB -6dB 0dB

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TDA7402 Table 26.
MSB D7 D6 0 1 0 1 D5 D4 D3 D2 D1

I2C bus interface Configuration audioprocessor II (13) (continued)
LSB Function D0 FD2 attenuation -6dB 0dB MD1 mode single ended differential

Table 27.
MSB D7 1 : 1 1 0 0 : 0 0 : 0 0 x D6 0 : 0 0 0 0 : 0 0 : 1 1 1

Speaker, subwoofer and mixer level-control (14-20)
LSB Function D5 0 : 0 0 0 0 : 0 0 : 0 0 1 D4 0 : 0 0 0 0 : 0 1 : 0 0 x D3 1 : 0 0 0 0 : 1 0 : 1 1 x D2 1 : 0 0 0 0 : 1 0 : 1 1 x D1 1 : 0 0 0 0 : 1 0 : 1 1 x D0 1 : 1 0 0 1 : 1 0 : 0 1 x +15 dB : +1 dB 0 dB 0 dB -1 dB : -15 dB -16 dB : -78 dB -79 dB Mute

The programming of all speaker, subwoofer and mixing level controls are the same.

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I2C bus interface Table 28.
MSB D7 D6 D5 D4 D3 D2 D1

TDA7402 Testing Audioprocessor (21)
LSB Function D0 0 1 0 0 0 0 1 1 1 1 0 1 0 1 0 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 Audioprocessor testmode off on Test-multiplexer Compander log amp. output Compander low pass output Compander DAC output 200kHz oscillator not allowed not allowed NB-hold internal reference Compander testmode off on Clock external internal AZ function off on SC-clock Fast mode Normal mode

0 1

Note:

This byte is used for testing or evaluation purposes only and must not set to other values than "11101110" in the application! Table 29.
MSB D7 D6 D5 D4 D3 D2 D1

Stereo decoder (22)
LSB Function D0 0 1 0 0 1 1 0 1 0 1 0 1 STD unmuted STD muted IN-gain 11 dB IN-gain 8.5 dB IN-gain 6 dB IN-gain 3.5 dB Input AM pin Input MPX pin

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TDA7402 Table 29.
MSB D7 D6 D5 D4 0 1 0 1 0 0 1 1 0 1 0 1 D3 D2 D1

I2C bus interface Stereo decoder (22) (continued)
LSB Function D0 Forced MONO MONO/STEREO switch automatically Pilot threshold HIGH Pilot threshold LOW De-emphasis 50s (37.5s(1)) De-emphasis 62.5s (46.9s(1)) De-emphasis 75s (56.3s(1)) De-emphasis 100s (75s(1))

1. If De-emphasis-Shift enabled (Subaddr.26/Bit7 = 0)

Table 30.
MSB D7 D6

Noise blanker I (23)
LSB Function D5 D4 D3 D2 D1 D0 0 1 0 0 0 0 1 1 1 1 0 0 1 1 0 1 0 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 Noise blanker off Noise blanker on Low threshold 65mV Low threshold 60mV Low threshold 55mV Low threshold 50mV Low threshold 45mV Low threshold 40mV Low threshold 35mV Low threshold 30mV Noise controlled threshold 320mV Noise controlled threshold 260mV Noise controlled threshold 200mV Noise controlled threshold 140mV Overdeviation adjust 2.8V Overdeviation adjust 2.0V Overdeviation adjust 1.2V Overdeviation detector OFF

0 0 1 1

0 1 0 1

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I2C bus interface Table 31.
MSB D7 D6 D5 D4 D3 D2 D1

TDA7402 Noiseblanker II (24)
LSB Function D0 0 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 PEAK charge current low high Fieldstrength adjust 2.3V 1.8V 1.3V OFF Blank Time FM / AM 38s / 1.2ms 25.5s / 800s 32s / 1.0s 22s / 640s Noise rectifier discharge resistor R = infinite RDC = 56k RDC = 33k RDC = 18k Strong multipath influence on PEAK 18k off on (18k discharge if VMPout< 2.5V)

0 1

Table 32.
MSB D7 D6

AM / FM noiseblanker (25)
LSB Function D5 D4 D3 D2 D1 D0 0 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 Stereo decoder mode FM AM AM rectifier gain 6dB 8dB 10dB 12dB 14dB 16dB 18dB 20dB

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TDA7402 Table 32.
MSB D7 D6 D5 0 0 1 1 1 1 D4 0 1 0 1 D3 D2 D1

I2C bus interface AM / FM noiseblanker (25) (continued)
LSB Function D0 Rectifier cut off frequency 14.0kHz 18.5kHz 28.0kHz 56.0kHz must be "1"

Table 33.
MSB D7 D6

High cut (26)
LSB Function D5 D4 D3 D2 D1 D0 0 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 High cut off on max. high cut 2dB 5dB 7dB 10dB VHCH to be at 42% REF5V 50% REF5V 58% REF5V 66% REF5V VHCL to be at 16.7% VHCH 22.2% VHCH 27.8% VHCH 33.3% VHCH De-emphasis shift On Off

0 0 1 1 0 1

0 1 0 1

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I2C bus interface Table 34.
MSB D7 D6 D5 D4 D3 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 D2 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 D1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1

TDA7402 Fieldstrength control (27)
LSB Function D0 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 VSBL to be at 20.0% REF5V 23.3% REF5V 26.6% REF5V 30.0% REF5V 33.3% REF5V 36.6% REF5V 40.0% REF5V 43.3% REF5V 46.6% REF5V 50.0% REF5V 53.3% REF5V 56.6% REF5V 60.0% REF5V 63.3% REF5V 66.6% REF5V 70.0% REF5V Quality detector co-efficient a=0.7 a=0.85 a=1.0 a=1.15 HCC level shift (only level through MPD) 0.0V 500mV 1.0 V 1.5 V

Table 35.
MSB D7 D6

Multipath detector (28)
LSB Function D5 D4 D3 D2 D1 D0 0 1 0 0 1 1 0 1 0 1 Fast Load on off Bandpass Gain 6dB 12dB 16dB 18dB

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TDA7402 Table 35.
MSB D7 D6 D5 D4 0 0 1 1 0 1 0 1 0 1 D3 0 1 0 1 D2 D1

I2C bus interface Multipath detector (28) (continued)
LSB Function D0 Rectifier gain Gain = 7.6dB Gain = 4.6dB Gain = 0dB disabled Charge current at MP out 0.25A 0.50A Multipath on high cut decay time 2ms 10ms Multipath influence on PEAK discharge off -1V/ms

Table 36.
MSB D7 0 0 0 : 0 : 0 1 1 1 : 1 : 1 0 0 0 : 1 D6

Stereo decoder adjustment (29)
LSB Function D5 D4 D3 D2 0 0 0 : 1 : 1 0 0 0 : 1 : 1 0 0 0 : 1 0 0 1 : 1 0 1 0 : 1 D1 0 0 1 : 0 : 1 0 0 1 : 0 : 1 D0 0 1 0 : 0 : 1 0 1 0 : 0 : 1 Roll off compensation not allowed 7.2% 9.4% : 13.7% : 20.2% not allowed 19.6% 21.5% : 25.3% : 31.0% LEVEL gain 0dB 0.4dB 0.8dB : 6dB

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I2C bus interface Table 37.
MSB D7 D6 D5 D4 D3 D2 D1

TDA7402 Stereo decoder configuration (30)
LSB Function D0 0 1 0 1 0 1 0 1 1 x 1 x Multipath influence on high cut On Off Multipath influence on stereo blend On Off Level input over multipath detector(1) On Off Dual MPX mode On Off must be "1"

1

1

1

1

1

1. Using the multipath time-constants for stereo bland and high cut

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TDA7402 Table 38.
MSB D7 D6 D5 D4 D3 D2 D1

I2C bus interface Testing stereo decoder (31)
LSB Function D0 0 1 0 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 Main testmode off on Stereo decoder testmode off on Test signals F228 NB threshold Level for stereo blend Pilot magnitude VHCCL Pilot threshold VHCCH REF5V HOLDN NB peak AM rectifier VCOCON; VCO control voltage VSBL Pilot threshold Level for high cut REF5V Audioprocessor oscillator Off On must be "1"

Note:

This byte is used for testing or evaluation purposes only and must not set to other values than "11111100" in the application!

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Application information

TDA7402

9

Application information
Figure 37. Application diagram (standard configuration)
OUTLF OUTLR OUTRF OUTRR OUTSWL OUTSWR OUTSSL

220nF SEL 220nF SER 220nF FD1L+ 220nF FD1L220nF FD1R+ 220nF FD1R220nF FD2L+ 220nF FD2L220nF FD2R+ 220nF FD2R220nF AM 220nF MPX1 470nF

OUTLF SEL 1 30

OUTLR 29

OUTRF 28

OUTRR 27

OUTSWL 26

OUTSWR 25

OUTSSL 24 23 44 OUTSSR MD2G 220nF OUTSSR MD2G 220nF MD2 220nF MD1G 220nF MD1 47nF 10F MUX PAUSE

SER

2

FD1L+

3

43

MD2

FD1L-

4

42

MD1G

FD1R+

5

41

MD1

FD1R-

6

40

MUX

FD2L+

7

39 38 37

CREF ACOUTL ACOUTR 220nF

FD2L-

8

ACOUTL ACOUTR

FD2R+

9 36 10 35 11 34 13 33 32 16 12 AMIF LEVEL 14 MPIN 15 QUAL 17 SM 18 GND 19 SDA 20 SCL 21 VDD + VB1 = -9 AMIF LEVEL MPIN QUAL SMUTE SDA SCL 22 31

SWINR

FD2R-

SWINL

220nF

AM

ACINLF ACINLR ACINRF ACINRR

470nF

470nF

MPX

MPOUT

220nF

100nF
D00AU1161

Figure 38. Application diagram (Dual MPX mode)
OUTLF OUTRF OUTLR OUTRR OUTSWL OUTSWR OUTSSL

100nF SEL 100nF SER 220nF FD1L+ 220nF FD1L220nF FD1R+ 220nF FD1R220nF FD2L+ 220nF FD2L220nF FD2R+ 220nF FD2R100nF AM 100nF MPX1 470nF

OUTLF SEL 1 30

OUTLR 29

OUTRF 28

OUTRR 27

OUTSWL 26

OUTSWR 25

OUTSSL 24 23 44 43 42 OUTSSR MD2G MD2 MD1G 220nF 100nF

OUTSSR MPX2 VPX CONTROL MD1G

SER

2

FD1L+

3

FD1L-

4 41 5 40

MD1

220nF MD1 47nF 10F MUX PAUSE

FD1R+

FD1R-

MUX

6

FD2L+

7

39

CREF

FD2L-

8

38 37

ACOUTL ACOUTR 220nF

ACOUTL ACOUTR

FD2R+

9 36 10 35 11 34 13 33 32 16 12 AMIF LEVEL 14 MPIN 15 QUAL 17 SM 18 GND 19 SDA 20 SCL 21 VDD + VB1 = -9 AMIF LEVEL MPIN QUAL SMUTE SDA SCL 22 31

SWINR

FD2R-

SWINL

220nF

AM

ACINLF ACINLR ACINRF ACINRR

470nF

470nF

MPX

MPOUT

100nF
D00AU1158

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Package information

10

Package information
In order to meet environmental requirements, ST (also) offers these devices in ECOPACK packages. ECOPACK packages are lead-free. The category of second Level Interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com. Figure 39. LQFP44 (10x10) mechanical data and package dimensions
DIM. A A1 A2 b c D D1 D2 D3 E E1 E2 E3 e L L1 K ccc 0.45 11.80 9.80 2.00 8.00 0.80 0.60 1.00 0.75 0.0177 0.0394 3.5(m in.),7 (max.) 0.10 0.0039 0.05 1.35 0.30 0.09 11.80 9.80 2.00 8.00 12.00 10.00 12.00 10.00 1.40 0.37 mm MIN. TYP. M AX . 1.60 0.15 0.0020 MIN. inch TYP. MAX. 0.0630 0.0059

OUTLINE AND MECHANICAL DATA

1.45 0.0531 0.0551 0.0571 0.45 0.0118 0.0146 0.0177 0.20 0.0035 0.0079

12.20 0.4646 0.4724 0.4803 10.20 0.3858 0.3937 0.4016 0.0787 0.3150 12.20 0.4646 0.4724 0.4803 10.20 0.3858 0.3937 0.4016 0.0787 0.3150 0.0315 0.0295

Note: 1. The size of exposed pad is variable depending of leadframe design pad size. End user should verify "D2" and "E2" dimensions for each device application.

LQFP44 (10 x 10 x 1.40mm) Exposed Pad Down

7278839 C

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Revision history

TDA7402

11

Revision history
Table 39.
Date 26-Apr-2002 21-Jun-2004 26-Apr-2004 26-Apr-2006 23-Mar-2007 18-Sep-2008

Document revision history
Revision 1 2 3 4 5 6 Initial release Technical migration from ST-PRESS to EDOCS Revalidation Minor text changes. Document reformatted. Package change, text modifications. Content of the Table 18, Table 19 and Table 24 reworked to improve readability, no technical changes. Changes

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Document Number: 7051



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