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TPS7B63-Q1: Maximum delay from WD rising edge to WDO is pulled low

Part Number: TPS7B63-Q1

Hi team,

The datasheet mentions WDO is pulled low when rising edge of WD is detected in closed window.

Could you tell me how much is the maximum delay from WD rising edge to WDO is pulled low?

Regards,

Saito

  • Hey Saito-san, 

    Please allow 2-3 business days to get back to you on this. 

    Thanks, 

    McKyla

  • Hi Mckyla-san,

    Thanks. I asked customer to wait our feedback 2-3 business days.

    I will look forward hearing from you.

    Regards.

    Saito

  • Hey Saito-san, 

    Unfortunately, this is not something that is tested. This part is tested and spec'ed at R(ROSC) = 20kohms +/- 1%. But to estimate other values you can use the relationship between the watchdog window duration and the watchdog output resetting time to calculate the ms for a given R(ROSC) value. 

    Hope this helps! 

    Thanks, 

    McKyla

  • Hi McKyla-san,

    Thank you for your comments. But, I'm not clear how I answer to customer.

    Could you tell me how I can estimate the delay from WD become high in CW to WDO is pulled Low?

    Regards,

    Saito

  • Hey Saito-san, 

    For example if you would to estimate 40kohms = R(ROSC) 

    FSEL Low = tWD = R(ROSC)  (0.5 x 10-6

                         tWD = 20 ms

    FSEL High = tWD = R(ROSC)  (2.5 x 10-6

                         tWD = 100 ms

    (See same values in table 7.1 in datasheet) 

    How table for 40kohms = R(ROSC)  would look min and max were calculated using 10% tolerance on each side specified in Table 7.1. This does not account for resistance tolerances, but assume ideal resistor (add additional tolerances for rating of resistor). Additionally note that above 100kohms 10% tolerance does not hold. 

    tWD estimate 40kohms = R(ROSC)  18 20 22 ms
    90 100 110 ms

    tWD_RESET 40kohms = R(ROSC) 3.6 4 4.4 ms
    18 20 22 ms

    Please keep in mind that this is good estimate, but these values are not tested and specified in the datasheet. 

    Let me know if you have further questions. 

    Best,

    McKyla

  • Hi Mckyla-san,

    Unfortunately, this answer is not what I expected. I will contact you internally.

    Regards,

    Saito