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LIS3DH using too much power on custom board

SKein.1
Associate

I have a custom board that includes the LIS3DH. With the LIS3DH not populated, my board uses 0.009mA, but with the LIS3DH populated and not configured, it uses 0.135mA.

According the data sheet, it should be 0.011mA. The data sheet also says the LIS3DH is set to "Power Down Mode" by default.

Attached is the schematic of the LIS3DH on my custom board. Is it not connected correctly?

0690X00000BuYGJQA3.png

The pseudo-code to turn the LIS3DH off is:

LIS3DH_ADDRESS = 0x18 ;

REG1_REG = 0x20; //REG_1

REG1_VALUE = 0x00;

LIS3DH_WriteReg(LIS3DH_ADDRESS, REG1_REG, REG1_VALUE);

-- this is still using too much power.

Is it a software problem or hardware?

thank you,

Steve

1 REPLY 1
Eleon BORLINI
ST Employee

Hi Steve, I think that it could be mainly related to an HW root cause. The datasheet says at p.9: SDO/SA0 pin is internally pulled up. Refer to Table 3 for the internal pull-up values (typ.). If you connect the SDO pin to GND you create a path (even if not direct) from VBAT to GND causing an over-current consumption. Regards