UM0537 User manual STEVAL-MKI019V1 demonstration kit for the LIS302SG Introduction The STEVAL-MKI019V1 is a demonstration kit designed to provide the user with a complete, ready-to-use platform for the evaluation of the LIS302SG. The LIS302SG 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 Power-down and Self-test pins. October 2008 Rev 2 1/8 www.st.com Demonstration kit description 1 UM0537 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 PD PS Voltage Regulator 3.3V MEMS Sensor ST PSR S0 Output Buffer VXYZ Figure 2. 2/8 Buffered Output S1 Voutxyz Sensor Output MUX Output Top silk-screen for STEVAL-MKI019V1 board layout UM0537 Demonstration kit description Figure 3. STEVAL-MKI019V1 board photograph ref2 ref3 1.1 ref1 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 LIS302SG MEMS sensor is 0.65 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 3.3 V. The outputs (Voutx, Vouty and Voutz) of the LIS302SG 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 1 C ( x, y, x ) = ---------------------------------2 R out f t 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. 3/8 Demonstration kit description 1.2 UM0537 Driving Power-down and self-test signals The board allows the control of the Power-down and Self-test signals through the use of test points (marked J3 and J7, respectively) and jumpers. 1.2.1 Power-down When the jumper is removed from J3 (Power-down, Figure 3, ref1) the MEMS sensor is in normal mode, otherwise it is in power-down mode. 1.2.2 Self-test When the jumper is removed from J7 (Self-Test, Figure 3, ref2) the self-test feature is disabled. In order 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 LIS302SG sensor. 1.2.3 Multiplexed output The device provides an embedded multiplexer to allow the redirection of either the analog output signals Voutx, Vouty, and Voutz or of an auxiliary input signal onto a single pin for operation with a single channel A/D converter. Output selection can be achieved through jumpers J6 and J9 (S0 and S1, Figure 3, ref3). Refer to Table 1 for MUX configuration. Table 1. 4/8 MUX I/O table S1 pin S0 pin MUX status 0 0 Vout=Vout X 0 1 Vout=Vout Y 1 0 Vout=Vout Z 1 1 Vout=Aux_in PSR 2 1 J2 C1 2.2uF VDD 1 2 3 4 LE 1 2 3 4 U2 8 7 6 5 8 7 6 5 VDD R4 10K 1 2 1 2 1 2 1 2 J3 J7 J9 J6 C2 100nF R3 10K C3 10uF R2 10K R1 10K C4 100nF VDD Power_Supply 1 2 J1 6 5 4 3 2 1 PD ST S1 S0 Rsvd Rsvd 14 Aux_in Vdd Cx 4.7nF VoutY VoutZ GND VoutYq Cy 4.7nF VoutZq 8 J8 3 2 1 VoutYq VoutXq Aux_In Vout_Mux Vout_MuxBuff 9 10 11 12 13 U1 Motion Sensor Vout_mux Rsvd 1 2 3 4 5 6 7 TS924 VOUT1 VOUT4 V-1 V-4 V+1 V+4 VCC GND V+2 V+3 V-2 V-3 VOUT2 VOUT3 U3 Vout_Mux Vout_MuxBuff VYq Cz 4.7nF VDD VXq TS924 rail to rail Low noise Quad operational 1 2 3 J5 1 2 3 J4 14 Vout_MuxBuff 13 Vout_Mux 12 11 10 VoutZq 9 8 VZq VoutXq VoutYq VoutZq VXq VYq VZq Sensor Output Buffered Output Figure 4. VoutX 2 VoutXq7 UM0537 Schematic diagram Schematic diagram The schematic diagram of the STEVAL-MKI019V1 demonstration kit is shown in Figure 4. Schematic diagram for STEVAL-MKI019V1 board 5/8 Bill of material 3 UM0537 Bill of material The bill of material for STEVAL-MKI019V1 demonstration kit is provided in Table 2. Table 2. 6/8 Bill of material Item Quantity Reference Value 1 2 C2,C4 100 nF 2 1 C1 2.2 F 3 3 Cx,Cy,Cz 4.7 nF 4 1 C3 10 F 5 4 R1, R2, R3, R4 10 k 6 6 J1,J2,J3,J6,J7,J9 CON2 7 3 J4,J5,J8 CON3 8 1 U1 LIS302SG 9 1 U2 LE33 10 1 U3 TS924 UM0537 4 Revision history Revision history Table 3. Document revision history Date Revision Changes 24-June-2008 1 Initial release. 17-Oct-2008 2 Changed: Figure 4 7/8 UM0537 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries ("ST") reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST's terms and conditions of sale. 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