TPS3851: Watchdog timer is not working?

Part Number:TPS3851

Hi,

I have a question about the watchdog TPS3851. I would like to consult the design according to the manual, but it seems that the watchdog timer does not work;

The tests that have been done for TPS3851 are:

1. Press the reset button and output the reset signal normally;

2. The power supply voltage is reduced to about 3.1v, and the reset signal is output;

3. The pull up resistance R288 of SET1 was measured close to the SET1 end without short circuit with GND, and R288 was measured at high level close to SET1;

4. Remove TPS3851, and there is no soldering phenomenon