UC3625DWTR has no output waveform

Hi team,

Here's an issue from the customer may need your help:

After several debugging, the PWR VCC+16V, VCC+16V supply pins are all +16V normal. When the RC-OSC pin is set to 2.0V-3.6V, the voltage of PDC pin, PDB pin, PDA pin are all 0V and cannot get the waveform from the oscilloscope.

The PBA, PUB and PUC pins all have voltages between 1.7V and 3.0V. But neither can the square waveform be detected. What could be the possible reason?

Could you help check this case? Thanks.

Best Regards,

Cherry