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TPS7B63-Q1: Can WTS pin be connected OUT pin? TPS7B63-Q1 set standard watchdog mode.

Soichi Nishimura
Expert 5235 points
Part Number: TPS7B63-Q1

Hi team,

I have a question about TPS7B63-Q1.

Customer wants to use TPS7B63-Q1 as standard watchdog mode. Is TPS7B63-Q1 standard watchdog mode when WTS is connected OUT(5V) pin?

Regarding to pin FMEA consideration, customer hopes to avoid short condition between VBAT and GND condition.
In case of WTS has failure mode which is short to next pin which is GND pin, there is possiblity to happen VBAT-GND short condition if WTS is connected VBAT. So, customer don't want to connect WTS to VBAT, but they hope to connect WTS to OUT. Can WTS be connected OUT pin if TPS7B63Q1 set as standard watchdog mode?

Regards,

Nishimura

  • 0
    TI__Guru 55940 points

    Hi Nishimura,

    Yes, since WTS is a digital input, any voltage rail above 2 V (High-level Input Voltage) at the time that the watchdog is initialized will set TPS7B63-Q1 into standard watchdog mode.  The watchdog is disabled until PG transitions to logic high which means that Vout must be 89.6% (min) of its final value. 

    In your case this means that the watchdog will not be enabled until Vout is at least 4.48 V for a nominal 5 V output.  As such, connecting WTS to OUT will set TPS7B63-Q1 into the standard watchdog mode.

    Very Respectfully,

    Ryan