ST8R00
Micropower 1A synchronous step-up DC-DC converter
Features
Very low supply current: 500A (typ) Output voltage adjustable from 6V to 12V Output voltage accuracy: 2% Output current up to 1A Low ripple voltage: 5mV (typ) Synchronous rectification High 90% efficiency: VO = 9V (typ) Few external components Very small DFN8 (4x4mm) package ST8R00W, guarantees the lowest switching ripple when the device is used at light load conditions. The high switching frequency and internally limited peak inductor current permit the use of small, low-cost inductors. Only three external components are required: an inductor and two ceramic capacitors. The ST8R00 is suitable for use in equipment where low noise, low ripple and low supply current are required. The ST8R00 is available in a very small DFN8 4x4mm package.
DFN8 4x4mm
Description
The ST8R00 family of low quiescent current, synchronous PWM step-up DC-DC converters offer high efficiency even in light load conditions. The ST8R00 accepts a positive input voltage from 4 to 6V and provides an output voltage in the 6 to 12V range. The ST8R00 is developed in two versions: Burst mode and Continuous mode. The Burst mode version functions in discontinuous mode, allowing the device to maintain the regulated voltage in no load conditions by turning off the internal switches. The Continuous mode version,
Order codes
Part number ST8R00 (1) ST8R00W
(2)
Package ST8R00PUR ST8R00WPUR
Output voltages ADJ ADJ
1. Burst mode at light load 2. Full PWM mode
May 2007
Rev. 1
1/19
www.st.com 19
ST8R00
Contents
1 2 3 4 5 6 7 8 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Typical application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
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ST8R00
Block diagram
1
Figure 1.
Block diagram
Schematic diagram
LX Thermal OUT
INH
Inhibit
PGND
PWM Control
IN VREF
FB
PGND
GND
3/19
Pin configuration
ST8R00
2
Figure 2.
Pin configuration
Pin connections (top view)
Table 1.
Pin n 1 2 3 4 5 6 7 8 EXP pad
Pin description
Symbol LX PGND GND IN FB INH HV OUT GND Switching output Power ground Analog ground Power input for analog circuit Feedback Inhibit. Connecting the pin to a voltage higher than 2V = device ON. Connecting the pin to a voltage lower than 0.8V = device OFF, resulting in no current flow to the load Trimming (floating or connected to GND) Output voltage Exposed pad. Must be connected to GND Name and function
4/19
ST8R00
Typical application circuit
3
Figure 3.
Typical application circuit
Application circuit
VI
L=4.7H
IN INH
LX OUT R1
VO
ST8R00
CI=10F GND PGND
FB R2 CO=10F
5/19
Maximum ratings
ST8R00
4
Table 2.
Symbol VO VI VINH VLX ILX TSTG TOP
Maximum ratings
Absolute maximum ratings
Parameter Output voltage Input voltage Inhibit voltage LX pin voltage LX pin output current Storage temperature range Operating junction temperature range Value 16 6 6 16 Internally limited -50 to 150 -25 to 125 C C Unit V V V V
Table 3.
Symbol RthJC RthJA
Thermal Data
Parameter Thermal resistance junction-case Thermal resistance junction-ambient Value 10 50 Unit C/W C/W
Table 4.
Symbol ESD ESD
ESD Performance
Parameter ESD protection voltage ESD protection voltage HBM MM Test conditions Value 4 500 Unit KV V
6/19
ST8R00
Electrical characteristics
5
Table 5.
Symbol VO
Electrical characteristics
Electrical characteristics for the ST8R00 (VI = 5V, VINH = 2V, IO = 100mA, TJ = -25C to 125C, CI = CO = 10F(X7R), L = 4.7H unless otherwise specified.)
Parameter Output voltage
(1)
Test conditions
Min. 6
Typ.
Max. 12
Unit V V V V V nA A m
VSTART-UP Star t-up voltage VI VFB VFB_OFF IFB ISUPPLY Input voltage range Feedback voltage Feedback voltage Feedback current Supply current
IO = 400mA, VI rising 4 IO = 50mA IO = 0, VINH = 0 VFB = 0, VINH = 2V To be measured at VI, no load ILX = 400mA ILX = 400mA VLX = 4V, VFB = 2V, VINH = 0 VLX = 4V To be measured on LX pin To be measured on LX pin IO = 100mA, VO = 9V 0.8 1.195
3
3.5 6
1.22 0 600 500 300 300
1.245
RDSON_N Internal N channel RDSON RDSON_P Internal P channel RDSON ILX(leak) ILX(LIM) fOSC DTY Internal leakage current LX current limitation Oscillator frequency Max. oscillator duty cycle
0.5 3 1.2 90 80 90 90 2 1.4
A A MHz %
Eff
Efficiency
IO = 500mA, VO = 9V IO = 1A, VO = 9V
%
VINH_H VINH_L IINH TSHDN T HYS VO/VI VO/IO VO/VI TSTART
1.
Inhibit threshold high Inhibit threshold low Inhibit pin current Thermal shut down
(2) (2)
V VI = 4 to 6V, IO = 50mA VINH = VI = 5V 130 150 15 VI from 4 to 5.5V, IO = 500mA (2) VI = 5V, IO from 10mA to 500mA, VO = 7V (2) VI from 0 to 5V, IO = 500mA VINH from 0 to 5V, IO = 100mA -5 -5 -10 500 5 5 10 0.8 2 A C C %VO %VO %VO s
Thermal shut down hysteresis Line transient response Load transient response Star t-up transient Star t-up time
For VO higher than 9V the maximum output current capability is reduced according to LX current limitation
2. Guaranteed by design
7/19
Electrical characteristics
ST 8 R 0 0
Table 6.
Symbol VO
Electrical characteristics for the ST8R00W (VI = 5V, VINH = 2V, IO = 100mA, TJ = -25C to 125C, CI = CO = 10F(X7R), L = 4.7H unless otherwise specified.)
Parameter Output voltage
(1)
Test conditions
Min. 6
Typ.
Max. 12
Unit V V V V V nA mA m
VSTART-UP Star t-up voltage VI VFB VFB_OFF IFB ISUPPLY Input voltage range Feedback voltage Feedback voltage Feedback current Supply current
IO = 400mA, VI rising 4 IO = 50mA IO = 0, VINH = 0 VFB = 0, VINH = 2V To be measured at VI, VO = 7V, no load ILX = 400mA ILX = 400mA VLX = 4V, VFB = 2V, VINH = 0 VLX = 4V To be measured on LX pin To be measured on LX pin IO = 50mA, VO = 7V 0.8 1.195
3
3.5 6
1.22 0 600 10 300 300
1.245
RDSON_N Internal N channel RDSON RDSON_P Internal P channel RDSON ILX(leak) ILX(LIM) fOSC DTY Internal leakage current LX current limitation Oscillator frequency Max. oscillator duty cycle
0.5 3 1.2 90 85 90 90 2 1.4
A A MHz %
Eff
Efficiency
IO = 500mA, VO = 9V IO = 1A, VO = 9V
%
VINH_H VINH_L IINH TSHDN T HYS VO/VI VO/IO VO/VI TSTART
Inhibit threshold high Inhibit threshold low Inhibit pin current Thermal shut down
(2) (2)
V VI = 4 to 6V, IO = 50mA VINH = VI = 5V 130 150 15 VI from 4 to 5.5V, IO= 500mA (2) VI = 5V, IO from 10mA to 500mA, VO = 7V (2) VI from 0 to 5V, IO = 500mA VINH from 0 to 5V, IO = 100mA -5 -5 -10 500 5 5 10 0.8 2 A C C %VO %VO %VO s
Thermal shut down hysteresis Line transient response Load transient response Star t-up transient Star t-up time
1. For VO higher than 9V the maximum output current capability is reduced according to LX current limitation 2. Guaranteed by design
8/19
ST8R00
Typical characteristics
6
Figure 4.
Typical characteristics
(L = 4.7H, CI = CO = 10F) Voltage feedback vs temperature Figure 5. Feedback current vs temperature
1.3 1.28 1.26 1.24 1.22 1.2 1.18 1.16 1.14 1.12 1.1 1.1 -75 -50 -25 0 25 50
700 600 500
VI=5V, VINH=2V, No Inductor, No Bridge
VFB [mV]
IFB [nA]
VI=VINH=5V, IO=50mA
400 300 200 100 0 -100 -75 -50 -25 0 25 50 75 100 125 150 175
75
100 125 150 175
T [C]
T [C]
Figure 6.
Supply current vs temperature (for ST8R00W)
Figure 7.
Supply current vs temperature (for ST8R00W)
20 VI=VINH=5V, No Load 18 16 14 12 10 8 6 4 2 0 -75 -50 -25 0 25 50
20 ISUPPLY [mA] 15 10 5
VI=5,VINH=2V,No Load, VO@ 7V
I SUPPLY [mA]
@VO=7V
0 -75 -50 -25 0 25 50 T [C] 75 100 125 150 175
75
100 125 150 175
T [C]
Figure 8.
Supply current vs temperature (for ST8R00W)
Figure 9.
LX current limitation vs temperature
800 750 700 600 550 500 450 400 -75
VI=5V, VINH=GND, VFB=2V No resistors bridge and inductor directly to VI
ILX [A]
650
4 3.5 3 2.5 2 1.5 1 0.5 0 -75 -50 -25 0 25 50 T [C] 75
ISUPPLY [A]
VIN=VINH=5V, @VO<10%
-50
-25
0
25
50
75
100 125 150 175
100 125 150 175
T [C]
9/19
Typical characteristics
ST 8 R 0 0
Figure 10. Inhibit voltage vs temperature
Figure 11. Inhibit voltage vs temperature
3 2.5 VINH [V] 2 1.5 1 0.5 0
VI=4V, VINH from 0 to 2V, IO=50mA
ON OFF
3 2.5 V INH [ V ] 2 1.5 1 0.5 0 -75
VI=6V, VINH from 0 to 2V, IO=50mA
ON OFF
-75
- 50
-25
0
25
50 T [C]
75
100 125 150 175
-50
-25
0
25
50 T [C]
75
100 125 150 175
Figure 12. Line regulation vs temperature
Figure 13. Load regulation vs temperature
1 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 -75
VI= from 4V to 6V, IO=1A
VO@9.5V
1 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 -75
VI=5V, IO from 100mA to 1A
LINE [%VO/ VI]
LOAD [%VO/ IO]
VO@9.5V
-50
-25
0
25
50 T [C]
75
100 125 150 175
-50
-25
0
25
50 T [C]
75
100 125 150 175
Figure 14. Oscillator frequency vs temperature
Figure 15. Max oscillator duty cycle vs temperature
1.7 1.5 1.3 1.1 0.9 0.7 0.5 -75 -50 -25 0 25 50 T [C] 75 100 125 150 175
Dutycycle MAX [%]
PWM freq.[MHz]
VI=VINH=5V, No Inductor, No Load
100 97.5 95 92.5 90 87.5 85 82.5 80
VI=VINH=5V, VFB=GND, No Inductor
-7 5
-50
-25
0
25
50 T [C]
75
100 125 150 175
10/19
ST8R00
Typical characteristics
Figure 16. Internal leakage current vs temperature
Figure 17. Internal leakage current vs temperature
0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 -75
0.6 0.5 ILX (leak)[uA] 0.4 0.3 0.2 0.1 0 -0.1
VI=5 , VINH=GND, VFB=2V, VLX=4V, No Inductor
ILX (leak)[mA]
VI=VINH=5V, VFB=2V, VLX=4V, No Inductor
-5 0
-25
0
25
50 T [C]
75
100 125 150 175
-75
-50
-25
0
25
50 T [C]
75
100 125 150 175
Figure 18. NMOS switch on resistance vs temperature
Figure 19. PMOS switch on resistance vs temperature
500
VI=5V
500
VI=5V
400
400 RDSON-P [m ] 300 200 100 0
RDSON-N [m ]
300 200 100 0 -75 -50 -25 0 25 50 T [C] 75 100 125 150 175
-75
-50
-25
0
25
50 T [C]
75
100 125 150 175
Figure 20. Efficiency vs output current (for ST8R00W)
Figure 21. Efficiency vs output current (for ST8R00W)
1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00 0 100 200
VO@7V
VI= VINH=5V, L=10H, IO= from 0A to 1A
1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00 0 100 200
Efficiency [%]
Efficiency [%]
VO@7V VI= VINH=5V, IO=from 0A to 1A
300
400 500 600 IO [mA]
700
800
900 1000
300
400 500 600 IO [mA]
700
800
900 1000
11/19
Typical characteristics
ST 8 R 0 0
Figure 22. Output voltage vs input voltage (for Figure 23. Maximum output current vs output ST8R00W) voltage
12.00
125C
1.1 1 0.9
25C 0C -25C
10.00 8.00
Pc os
VI=VINH=5V
t= 6W
VO [V]
6.00 4.00 2.00 0.00 0
IO [A]
0.8 0.7 0.6
PMAX=6W
OPERATIVE ZONE
VI=VINH from 0 to 6V, IO=400mA
0.5 0.4 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5
1
2
3
4
5
6
VI [V]
VO [V]
Figure 24. Efficiency vs output current
100 90 80 70 60 50 40 30 20 10 0 0
Figure 25. Efficiency vs input voltage
100
Efficiency [%]
Efficiency [%]
90 80 70 60 50 40 3.5
VI=VINH= 5V, IO=100mA ST8R00 ST8R00W
ST8R00 ST8R00W
VI= VINH=5V, VO=9.5V
0.2
0.4
0.6
0.8
1
4
4.5
5
VI [V]
5.5
6
6.5
IO [A]
Figure 26. Efficiency vs input voltage
Figure 27. Inductor current (for ST8R00W)
10 0
Efficiency [%]
90 80 70 60
VI=VINH=5V, IO=500mA ST8R00 ST8R00W
VLX
50 40 3.5 4 4.5 5
VI [V]
ILX
5.5
6
6.5
VI=5V ,VINH= 2V, L=4.7H, CI=CO=10F, No Load, T=25C
12/19
ST8R00
Typical characteristics
Figure 28. Load transient
Figure 29. Line transient
VI
VO
VO
IO
VI=VINH=5V, IO=from 10mA to 500mA
VI=VINH from 4V to 5.5V, IO=500mA, 20s
Figure 30. INH transient
Figure 31. Inrush current
VINH
VO IO
VI=6, VINH from 0V to 2V, IO=1A
VI=4.5, VO=7V, VINH from 0V to 3V, IO=0, L=10H
13/19
Package mechanical data
ST8R00
7
Package mechanical data
In order to meet environmental requirements, ST offers these devices in ECOPACK packages. These packages have a Lead-free second level interconnect. 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.
14/19
ST8R00
Package mechanical data
DFN8 (4x4) Mechanical Data
mm. Dim. Min. A A1 A3 b D D2 E E2 e L 0.40 0.23 3.90 2.82 3.90 2.05 0.80 0 Typ. 0.90 0.02 0.20 0.30 4.00 3.00 4.00 2.20 0.80 0.50 0.60 0.016 0.38 4.10 3.23 4.10 2.30 0.009 0.154 0.111 0.154 0.081 Max. 1.00 0.05 Min. 0.031 0 Typ. 0.035 0.001 0.008 0.012 0.157 0.118 0.157 0.087 0.031 0.020 0.024 0.015 0.161 0.127 0.161 0.091 Max. 0.039 0.002 i nch.
7869653B
15/19
Package mechanical data
ST8R00
Figure 32. DFN8 (4x4) Footprint Recommended Data
16/19
ST8R00
Package mechanical data
Tape & Reel QFNxx/DFNxx (4x4) Mechanical Data
mm. Dim. Min. A C D N T Ao Bo Ko Po P 4.35 4.35 1.1 4 8 12.8 20.2 99 101 14.4 0.171 0.171 0.043 0.157 0.315 Typ. Max. 330 13.2 0.504 0.795 3.898 3.976 0.567 Min. Typ. Max. 12.992 0.519 inch.
17/19
Revision history
ST8R00
8
Table 7.
Date
Revision history
Revision history
Revision 1 Initial release. Changes
23-May-2007
18/19
ST8R00
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