cancel
Showing results for 
Search instead for 
Did you mean: 

Does powering LSM6DS3 off pull down I2C lines?

Levi DeLuke
Associate
Posted on December 20, 2016 at 17:32

I am using the LSM6DS3 component in a design. I've used the component in the past (and always liked it), but never in this capacity. I am using I2C for communication with 10k pull up resistors and am powering on/off the sensor with a separate power bus than my micro controller. I have the interrupt pins connected to my micro controller, although they are not in use. 

The issue I am experiencing is that when the power for the sensor is turned off, the I2C lines are being pulled low. When the power for the sensor is pulled high, the I2C lines are high as expected and I can communicate to other peripherals on the I2C bus. In effect, powering down the sensor is pulling down the entire I2C line, drawing extra current in my system and preventing other I2C communication. 

Is this a problem you can provide insight on? I wasn't sure if the module supported this mode of operation, where the power was off while the I2C bus is used for other communication. Would this cause current to flow from the I2C lines in to the sensor? Would it have something to do with the interrupt pins? 

1 ACCEPTED SOLUTION

Accepted Solutions
Miroslav BATEK
ST Employee
Posted on December 21, 2016 at 17:42

The LSM6DS3 is draining current from I2C lines through ESD diodes to Vcc pins, which cause the issue you described.

I would suggest rather to switch the sensor to power down mode than disconnecting the Vcc, otherwise you would have to disconnect also I2C lines.

The current consumption in power down mode is only 6uA.

View solution in original post

2 REPLIES 2
Miroslav BATEK
ST Employee
Posted on December 21, 2016 at 17:42

The LSM6DS3 is draining current from I2C lines through ESD diodes to Vcc pins, which cause the issue you described.

I would suggest rather to switch the sensor to power down mode than disconnecting the Vcc, otherwise you would have to disconnect also I2C lines.

The current consumption in power down mode is only 6uA.

Posted on December 21, 2016 at 20:38

Thank you for the response! That makes sense and is as expected! I appreciate the input, I'll evaluate a few different options then. -Levi