TPS3851: Design review and queries

Apurva Agre

Part Number: TPS3851

Tool/software:

Hello,

In one of our designs, we are using the TPS3851H33EDRBR watchdog timer IC. In our design output of Watchdog timer (WDO and RESET ) are used to RESET STM32 controller. SET1 is controlled by STM32 controller and MR is provided by another processor. I want to ask that, if SET1 is low then can we RESET STM32 by making the MR pin low which is controlled by another processor?

We want twd=20sec hence we chose Ccwd=0.27uF is the calculation is correct? Can you please review the attached design circuit if it is functionally correct or not and please suggest if any changes are required.

over 1 year ago

0 Jesse Villanueva over 1 year ago

TI__Mastermind 18620 points

Hi Apurva,

Thank you for your question, Yes, the MR pin can be pulled low, asserting the RESET pin while SET1 is low and Yes, the Ccwd=.27uF will give you Twd = 20.9s.

I have reviewed the schematic and everything looks good to me.

Jesse

0 Apurva Agre over 1 year ago

Prodigy 170 points

Hello Jesse,

Thanks for the response. I have one more query about this design. In case if we want to REST controller whenever VDD (VDD ranges from 1.8V to 3.6V) goes below 2.5V should we use TPS3851H25EDRBR in our design?

0 Jesse Villanueva over 1 year ago in reply to Apurva Agre

TI__Mastermind 18620 points

Hi Apurva,

For the H33 the voltage threshold is 3.069V while the H25 is 2.325V, what would be the lowest voltage that your design can tolerate?

Jesse

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TPS3851: Design review and queries