UM0536 User manual
STEVAL-MKI016V1 demonstration kit for the LIS344AL
Introduction
The STEVAL-MKI016V1 is a demonstration kit designed to provide the user with a complete, ready-to-use platform for the evaluation of the LIS344AL. The LIS344AL is a lowpower 3-axis linear capacitive accelerometer that includes a sensing element and an IC interface capable of taking information from the sensing element and providing an analog signal to an external application. In addition to the MEMS sensor, the system includes a linear voltage regulator and a rail-torail low noise quad amplifier configured as a non-inverting buffer, making both direct sensor outputs and buffered sensor outputs available to the user. The kit also provides an easy way to control the Self-test pin.
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Demonstration kit description
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Demonstration kit description
The block diagram of the demonstration kit and the layout of the board are shown respectively in Figure 1 and Figure 2, while the full board photo of is provided in Figure 3. Figure 1. Demonstration board block diagram
PS
Voltage Regulator
3.3V MEMS Sensor ST
PSR
Output Buffer
VXYZ Buffered Output
Voutxyz
Sensor
Output
Figure 2.
Top silk-screen for STEVAL-MKI016V1 board layout
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UM0536 Figure 3. STEVAL-MKI016V1 board photograph
Demonstration kit description
ref1
1.1
Operating the demonstration kit
To operate the demonstration kit it is necessary to supply it through the connector marked J1 (PS) with a dc voltage between 3.7 V and 18 V. The suggested supply voltage is 5 V. The typical current consumption of the LIS344AL MEMS sensor is 0.69 mA, while the typical current consumption of the whole board is in the range of 6 mA. The voltage applied to the board is then regulated through a linear voltage regulator which supplies the MEMS sensor at 3 V. The outputs (Voutx, Vouty and Voutz) of the LIS344AL linear accelerometer are band limited through the use of three 4.7 nF capacitors (Cx, Cy and Cz) which, together with the sensor's 32 k output resistor Rout, create a single-pole low-pass filter with a cut-off frequency of approximately 1 kHz. If a different cut-off frequency ft is required, the user should replace the above capacitors with components having values derived using the following formula: Equation 1
--C ( x, y, x ) = ----------------1--------------2 Ro u t ft
As mentioned above, the STEVAL-MKI016V1 makes both the direct sensor outputs and the buffered signals available through two separate connectors: J4 (Sensor Output) and J3 (Buffered Output). Specifically, the three channels are made available from the left to right of the board in the order Voutx, Vouty and Voutz. The buffering of the sensor outputs is achieved through the use of a rail-to-rail low-noise quad-amplifier configured as a non-inverting buffer.
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Demonstration kit description
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1.2
Driving the ST (self-test) signal
The board allows the control of the self-test signals through the use of a jumper (J7).
1.2.1
Self-test
When the jumper is removed from J7 (Self-Test, Figure 3, ref1) the self-test feature is disabled. To activate the self-test feature, the jumper must be inserted into J7. When this function is activated the seismic mass of the sensor is moved by means of an electrostatic test-force, simulating a definite input acceleration. Under these conditions the sensor outputs will exhibit a voltage change in their DC levels as specified in the datasheet of the LIS344AL sensor.
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Figure 4.
J3 TS9 24 rail to rail Low noise Qu ad operational amplifier 1 2 3 VX VY VZ Buffered Output
LExx linear voltage regulator cas e: SO8 or TO92
U1 LE xx Vo ut X Vo ut Y Vo ut Z U3 VX J1 C2 10 0n F Vo ut Y VY TS9 24 VD D C3 10 uF 16 14 15 13 VD D NC Res 1 FS ST GN D NC PD GN D GN D Vo ut Z NC 9 Cy Vo ut Y 10 Vo ut Y NC 11 Cx Vo ut X 2 3 VD D 4 VD D NC 12 Vo ut X U4 LIS34 4 + C4 10 0n F Pow er_ Supp ly 1 2 VD D Vo ut X
J4 1 2 3 Sens or Output
VD D
Schematic diagram
J2
U2
1 2
1 2 3
ps r
C1 2. 2uF
1 2 3 4
1 2 3 4
8 7 6 5
8 7 6 5
LE xx
1 2 3 4 5 6 7 VO UT1 VO UT4 V-1 V-4 V+1 V+4 VCC GN D V+2 V+3 V-2 V-3 VO UT2 VO UT3
14 13 12 11 10 9 8 VZ
Vo ut Z
Fu ll Scale
1 2 3
J5
Schematic diagram for STEVAL-MKI016V1 board
Sel f Test
1 2 3 5 6 7 8
J7 VD D
Vo ut Z Cz
Po wer Down R1 10 K
1 2
The schematic diagram of the STEVAL-MKI016V1 demonstration kit is shown in Figure 4.
Schematic diagram
J6
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Bill of material
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Bill of material
The bill of material for STEVAL-MKI016V1 demonstration kit is provided in Table 1. Table 1. Bill of material
Item 1 2 3 4 5 6 7 8 9 10 Quantity 2 1 3 1 1 3 4 2 1 1 Reference C2,C4 C1 Cx,Cy,Cz C3 R1 J1,J2,J6 J3,J4,J5,J7 U2 U3 U4 Value 100 nF 2.2 F 4.7 nF 10 F 0 CON2 CON3 LE30 TS924 LIS344AL
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Revision history
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Revision history
Table 2.
Date 24-June-2008
Document revision history
Revision 1 Initial release. Changes
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