MAX9925 1Hz~10Hz output error

Hi,

We are testing MAX9925 with a signal generator. MAX9925 working mode is  A1( ZERO CROSSING and ADAPTIVE PEAK THRESHOLD are enabled.)  We find MAX9925 cannot work properly at frequency between 1Hz and 10Hz.

For example, when input is 1Hz, sometimes the output of MAX9925 is 2.x Hz, 4.x Hz, 12.x Hz or more. The output error is randomly. This happens when the input frequency is from 1Hz to 10Hz. When the frequency is 10Hz or higher,  the chip output is OK.

We check the data sheet and cannot find any description about frequency range.

Our question is:

1. What is the chip working frequency range?

2. There is watchdog inside the chip. Does this watchdog module generate the issue when input signal frequency is between 1Hz and 10Hz? How to shutdown this watchdog?

3. How does the chip mode configuration pin work?  Does the chip use the pin power-on status to configure the mode?   Can we use MCU to change ZERO_EN and INT_THRS online?

Thank you very much.