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DS90UB933-Q1: Power Down w/ PDB

TRM
Intellectual 1785 points
Part Number: DS90UB933-Q1

Hi,

Got two quick questions I was hoping for some clarification on...

  1. How long does PDB have to be pulled low before the device starts to power down -- Is it immediate or is there some de-bouncing/delay time?
  2. Can you interrupt the device power down sequence or, once started, does the device have to be completely restarted?
    1.  Would you have to redo the entire startup timing diagram (d/s figure 8-1)

Thanks
Tyler

  • 0
    TI__Guru** 107740 points

    Hello Tyler,

    1) you need to pull-down PDB for 2ms to make sure the device is completely in power down.

    2) I did not get your question!!

    Nevertheless, there is no power-down sequence requirement. 

  • 0 in reply to Hamzeh Jaradat
    TI__Intellectual 1785 points

    Hi Hamzeh,
    Appreciate the response.

    To clarify my question -- my customer is looking at a worst case analysis where the PDB pin might momentarily be shorted to ground.
    If that were to happen, what would be the consequences?

    • Would the device start the shut down process immediately?
    • If the short is cleared prior to 2ms, would you be able to continue operation as normal or would an entire shutdown/restart cycle be required?

    Thanks!

    Tyler

  • 0 in reply to TRM
    TI__Guru** 107740 points

    Hello Tyler, 

    thanks for the clarification!

    - Yes, this device will start the shut down process immediately.

    - If cleared prior to 2ms, the device may enter unknown state, hence it is required to pull PDB down for min. 2ms and then continue normal operation.