I am testing the ICS-40618 Analog MEMS Microphone and I am testing with the EV_ICS‐40618‐FX Evaluation Module. I have two different power supplies, both have isolated outputs. When I connected one supply (PS1) and input a 16KHz sound wave to the microphone, the output from the microphone is as expected and clean (See attachment SDS00010.jpg). When I connect to the other power supply (PS2), and input the same 16KHz wave to the microphone, the output is attenuated and distorted (See attachment SDS00011.jpg). I thought perhaps it is a ground problem, but I have checked and verified that PS2 output is indeed isolated from the AC input and Earth ground. I have also scoped both power supplies' outputs and compared their noise, and both seem similar. I was supplying 3.00V to the mic during this test. Anyone have any ideas of what could be going on?