Supply for LIS3DSH

[sebin sebastian]

Posted on June 28, 2018 at 09:26

Hello,

I want to power up  LIS3DSH from my controller. The source current provided by the controller is 4mA.My device powered  from coin cell battery , so in order  to reduce the power consumption i want to de-activate all the peripherals in their non active states(power down mode also reduce my battery life).Please find the  attached image.  

1)If the supply from controller the LIS3DSH need any BULK and DECAPS

2)Is the CS pin take any current?

3)Is any internal pull-up in the SEL pin?

With Regards,

Sebin Sebastian 

[Miroslav BATEK]

Posted on July 02, 2018 at 15:17

1) Yes, decoupling capacitors are needed as described in datasheet. It is question if you MCU is able to charge the big capacitor from GPIO pin.

2) The current to CS if connected to VDD_IO is negligible.

3) Yes, there is internal pull-up on SEL pin so it is better to connect it to VDD_IO, to reduce the current consumption.

[sebin sebastian]

Posted on July 03, 2018 at 06:08

Thanks Miroslav for your support.

I have some more questions.

1)How much current should the i2c pins take? It is not mentioned in the datasheet.

2)What is the maximum value of resistor to use as the i2c pull up?

3)Is there any pull up needed for INT1/DRDY ?

Regards,

Sebin Sebastian

[Miroslav BATEK]

Posted on July 04, 2018 at 17:45

1) The current through I2C will be mainly dependent on pull-up resistors, which defines the current when the state is low.

 2) It is hard to say, it depends on the length of the track, I2C frequency, ... You will have to test the reliability of the communication. 

3) No pull-up is needed on INT1/DRDY pin.