Why is LSM6DSL using so much current in power-down?

[Cars Smu]

Posted on June 16, 2018 at 05:12

We are seeing a large current draw when the LSM6DSL is in power-down mode, or low-power mode. The current measured is roughly 120 uA. IC is wired for I2C. We have an identical setup with a LIS3DH that does not have this issue.

Is there a register we need to change? Again , this 120 uA appears when power is supplied to the IC.

LSM6DSL Connections:

SDO: Unconnected

SA0:  Unconnected

SDx:

Connected to 

Ground

SCx:

Connected to 

Ground

INT1: Floating

INT2: Floating

CS: External pull-up with 10k

SCL: Connected to MCU i2c lines and other I2C devices - External pull-up with 10k

SDA:

Connected to MCU i2c lines and other I2C devices - External pull-up with 10k

#power-consumption #lsm6dsl

[Miroslav BATEK]

Posted on June 18, 2018 at 12:09

SA0 cannot be unconnected.

It must be connected to GND or VDDIO.

[Cars Smu]

Posted on June 19, 2018 at 02:50

Hi Miroslav,

Thank you for your reply. Could you elaborate ? The IC works fine with SA0 floating. Are you saying that extra current is drawn when this pin is left floating? If so,  why is the documentation not more explicit ? Or did we miss something? 

Would enabling this pull-up help?  

'Default: Input without pull-up. Pull-up is enabled if bit SIM = 1 (SPI 3-wire) in reg 12h.'

Thanks again for your help, much appreciated.

[Miroslav BATEK]

Posted on June 19, 2018 at 16:24

You can try to enable SPI 3-wire in reg 12h or try to connect the SA0 pin to VDDIO or GND.

If it will not help, please share your schematics.