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TPS3431: TI - TPS3431 (WDT) schematic review

Paul Lei
Prodigy 160 points
Part Number: TPS3431

Hi TI service team,

This is Paul from ZT hardware team.

Could you help to review it and feedback your comments for my design ?

Thank you very much.

WDT:

TI_TPS3431_SCH_CHECK_V1.0_20230619.pdf

Note1: Please regard all empty parts as stuffed components (unstuffed components: R1387/R1389/R1382)

Note2: WDI is used to monitor SMBus SDA status to react with RST_N from WDO_N

TI_TPS3431_SCH_CHECK_V1.0_20230619 (with WM).pdf

  • 0
    TI__Genius 13495 points

    Hi,

    The schematic looks OK for the t_WD value, but it is unclear to me how the t_rst value is achieved. TPS3431 does not have a CRST pin and has a t_rst of 200ms listed in the Timing Requirements Table (Section 6.6 of datasheet). How are you achieving a 10ms t_rst?

    Best regards,

    Ridge

  • 0 in reply to Ridge Lahti
    Prodigy 160 points

    Hi Ridge,

    Thanks for your confirmation about t_WD.

    Is it also ok of my HW circuit design ?

    Sorry about that.

    I just type a random value into your calculator for complete data results, but TPS3431 doesn't have CRST pin in it.

    Please ignore t_RST value in my attached picture.

    Thanks a lot.

    Best Regards,

    Paul Lei

  • 0 in reply to Paul Lei
    TI__Genius 13495 points

    Hi Paul,

    The top schematic looks OK as long as R1382 (pull up from CWD to VDD) remains unpopulated. When using a capacitor to configure the timing on CWD, the pullup resistor must not be used.

    On the bottom schematic, is it supposed to be the same as the top schematic? I notice that R1383 is populated and it should not be if the CWD capacitor is used to configure the timing.

    Best regards,

    Ridge Lahti

  • 0 in reply to Ridge Lahti
    Prodigy 160 points

    Hi Ridge,

    Yes, R1382 for CWD pull-up is unstuffed like datasheet mentioned for timing configuration (t_WD).

    Yes, you're right, these two files are the same schematic image.

    To sum up, my schematic seems ok from your point of view, because I have unstuffed R1382/R1383 for both TPS3431 HW design.

    Thanks a lot.

    Best Regards,

    Paul Lei