Mems microphone unstable sensitivity – Infineon Developer Community

We made new mems microphone package based on Infineon MEMS and ASIC.

we tried to calibration this package. however, to start calibration,when the package is applied bias voltage, the initial sensitivity of Mems microphone is slightly increasing from -47.2dB to -46.9dB, it took about 10sec and it settled a stable senstivity value. About 0.3dB variation occured, a certain package has a 0.6dB variation. What kinds of causes can make this problem? SNR is OK. THD is OK. Freq. response is OK.AOP is OK. But even after calibration, this phenomenon still happen.

Could you recommend any solution and the theoretical explanations for this issue?

I really appreciate if I get the answer from here.

Thanks.