DRV8705-Q1: Sense amp gain

Tool/software:

Hi team,

My customer is evaluating DRV8705-Q1 in their new project, now they met below issue, could you please help review and give some suggestions? Thanks!

The customer found in actual testing that the gain of current shunt amp was less than 40. Below is their test results.

They set the Gain=40 without resistor place in the Pin Gain. (The schematic is original setting)

They have tried the following tests.

1.Change the C725 from 100pF to 10nF, no improvement.

2.Change the Varef power supply , same as DVDD(Vcc1_5V)

3.Remove the R710 , no improvement

Given the result, the Varef value will influence the current amp gain , but the issue still not be solved.

Do you have any comments on optimizing the issue? Thanks.

Regards,

Ivy