• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 61 subscribers
  • Views 276 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS3850-Q1: Vsense : 3.7 - 4.1V, standard watchdog timer

Shinji Tsuji
Genius 13068 points
Part Number: TPS3850-Q1
Other Parts Discussed in Thread: TPS3820-Q1, TPS3823, TPS3823-Q1, TPS3851, TPS3851-Q1

Hi team,

I am looking for a supervisor chip(AEC-Q100 must) that have Vsense = 3.7V to 4.1V range and standard watchdog function.

Do you have such a device?

So far I could only found TPS3850-Q1 which has adjustable Vsense, but it has window watchdog.

Since I don't want to change the system software already available, window watchdog doesn't match the requirement.

Or is there a way to disable lower boundary of TPS3850-Q1 watchdog function to use it as standard watchdog?

regards,

  • 0
    TI__Genius 12630 points

    Shinji,

    Does Vsense monitor only undervoltage? If so, I think TPS3851-Q1 is the correct device as this is undervoltage monitor with standard watchdog.. This will require external resistor divider on VDD because there is no fixed threshold for TPS3851 between 3.7V and 4.1V. TPS3823-Q1 will also provide undervoltage monitoring with standard watchdog although the timeout is fixed to either 200ms (TPS3820-Q1) or 1.6 seconds (TPS3823/4/8-Q1).

  • 0 in reply to Michael_DeSando
    TI__Genius 13068 points

    Hi Michael,

    Thank you.

    Do you mean the sense voltage level can be adjusted by resister divider from the target rail to the VDD?

    Is there a calculation sheet for that? I wonder Icc will affect the accuracy.

    I also need adjustable reset delay.

    Does TPS3851-Q1 support adjustable reset delay?

    regards,

  • 0 in reply to Shinji Tsuji
    TI__Genius 12630 points

    Shiji,

    You are correct that the accuracy will decrease by using an external resistor to change the threshold. Depending on the resistor values you choose, there is tradeoff between accuracy and Iq. The calculation for calculating the new sense threshold follows a voltage divider equation: New sense voltage = device threshold * (Rtop + Rbottom) / Rbottom

    TPS3851-Q1 does not support programmable reset delay. Only TPS3850-Q1 has programmable reset delay.