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Original question:

TPS3813K33 reseting immediately after power up.

Linux/TPS3813: TPS3813 RESET do low in no WDI rising

Stoyan Daskalov
Prodigy 60 points
Part Number: TPS3813
Other Parts Discussed in Thread: TPS3850, TPS3431, TPS3430, TPS3851, NE555

Tool/software: Linux

Hello,

I have issue with TPS3813 the RESET do LOW even if no WDI rising impulse.

Last think i test was WDI connected directly to GND. Regarding to datasheet the RESET have to go LOW if no pulse to WDI after first rising impulse. In this case there no rising pulse and RESET should stay HIGH.

My application needs around 1 min to boot up.

Is this IC can be used in my application?

Is the datasheet is OK? "However, after the first WDI pulse low-to-high transition is detected, the lower boundary function of the window is enabled. All further WDI pulses must fit into the configured window frame"

  • 0
    TI__Genius 12630 points

    Linux,

    Unfortunaltey TPS3813 is not the correct device for you as this device does not have watchdog disable. This means that if no rising pulse is detected within the upper boundary time, the reset will assert. The maximum timeout for this device is ~25 seconds.

    The best device for you is TPS3850 if you want a window watchdog meaning the device will detect early time faults and late time faults.

    Or you can use TPS3851 which only detects late time faults. Both TPS3850 and TPS3851 also monitor a voltage. If you do not need to monitor a voltage, you can use TPS3430 or TPS3431.

    The reason these devices will work for your application is because the Watchdog can be disabled during power up. Once the system boots up, you can enable the watchdog to begin monitoring on WDI.

    Please let me know if you have any additional questions or need any more support. Thanks!

  • 0 in reply to Michael_DeSando
    Prodigy 60 points

    Hello, thank you for the fast replay.

    TPS3430 look like ok, but i don't like VSON package, and also is needed additional GPIO to enable WDT after system boot-up.

    The price in my regular suppliers is almost 6 USD is cost almost 1/3 of the hole device. May be i can make WDT based on NE555