TPS65381-Q1

Livio,

 I am looking into this and will get back to you soon.

Hecules forum support

Livion,

The only possible way to switch from Standby to reset state is to either trigger an level on IGN or to trigger an wakeup pulse  on CANWU. Hence would recommend you to facilitate either one  . i would not recommend leaving these pins unconnected.

Hercules forum support

Thanks Hari,

If I choose the first solution (IGN pin) is sufficient to connect a 10Kohm resistor between pin IGN and pin VBATP ??

Thanks

Livio

Such a design would work if the rising edge of VBAT is fast enough (based on bench test, 20ms is fine).

Otherwise, if this rising edge is slow, i.e. 300ms, the TPS device will release the reset before VBAT gets to 5.8v (the min voltage to operate for TPS65381), and then cause a TPS65381 BIST test failure. Eventually, you will find your TPS device staying in safe state.

Anyway, the TPS65381 not only checks its output voltage like the 1.2v and 3.3v, but also checks the VBAT. So, in theory, it requires sth else to tell it "power is good", otherwise, it might treat the power up time as "low VBAT detected" and go to safe mode.

Regards,

Haixiao

if the CANWU pin isn't to be used, can you advise where to tie it? 

Tie or pull to GND.