TPS3851: Could be Watchdog timing capacitor of Ccwd bigger than 1uf?

Luck Wu,

The accuracy (min, typical, max distribution) for timing will get worse once you get larger than 1uF. It is not recommend to use a capacitor larger than 1uF. If you do choose to use a larger capacitor, be sure to do your testing across all operating conditions to make sure it meets your criteria. We can not guarantee the performance of any capacitor larger than 1uF because TI has not tested for that condition. The device will not become damaged but the timing accuracy will become wider and thus harder to predict. I hope this answers your question!

-Michael