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LM3710/LM3711

Thibault
Intellectual 295 points
Other Parts Discussed in Thread: LM3710, TPS3823, TPS3110

Hello,

I want to monitor a clock presence and thought about using a supervisory IC with a watchdog input, like the LM3710. 

I've some questions about this one: 

- Is there a minimum WDI period/low time/high time requirement for the WDI transition detection?

- After watchdog has engaged reset, how can this signal be deasserted?  From the figure 1, I think that it is after tRP laps following one of this event : VCC higher than VRST+VRSTH, MR higher than VMRT+VMRTH or WDI transitions? (Hence, using this IC with a uP, the only way to restart is to cycle power or push an MR button?)

  • 0
    TI__Mastermind 41035 points

    Hi Thibault,

    1) I do not see a spec of the minimum pulse width you can pulse the WDI pin in the LM3710 datasheet. I recommend using the TPS3110 or TPS3823. This is speced as tw in the datasheet.

    2) After the time-out period of the WDI signal, the RESET signal goes low for a period speced as td (time delay) and deasserts on its own. This can be seen in the timing diagrams also on the datasheet.

    Regards,

    Darwin