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TPS3808-Q1: About Manual reset

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Replies: 3

Views: 236

Part Number: TPS3808-Q1

Hi team.

My customer designed reset circuit as the below. 

They added pull-up resistor(R2 : 4.7kohm) between SENSE to /MR.

If MCU does not control /MR(/MR input signal is High) and when output voltage of LM43602 is stable, could additional pull-up resistor cause problems with the output?

Could pull-up resistor have a bad effect on the circuit?

Please refer to LM43602-Q1 circuit below.

Please check and reply ASAP.

Thank you

  • Hi Charles,

    I would not use a resistor on MR and SENSE/VDD. This is because the MR pin of the device already has a internal pull up resistor. This resistor is not needed.

    -Marcoo

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  • In reply to Marcoo Z:

    Hi Marcoo

    I knew that it has internal resistor.
    I was wondering if there was a problem when adding a pullup resistor.
    My customer already shipped a product that added a pullup resistor.
    They has inquired as to whether the added pull-up resistor is likely to cause reset problems.
    Will there be a reset issue if when it is no signal on the MR pin due to the additional pullup resistor?

    Thank you.
  • In reply to Charles Jeon:

    Charles,

    There is no problem at all from using external pull-up resistor. When there is no signal on /MR, the /MR pin will pull-up via the external and internal pull-ups and prevent any reset.

    Please let me know if you have any other questions. Thanks!

    -Michael D

    Michael DeSando

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