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TIC12400-Q1: In polling mode, when does ADC or Comparator time start?

Adam Torma
Mastermind 45350 points
Part Number: TIC12400-Q1

E2E, 

For TIC12400-Q1, each input pin have some small cap.  Polling mode,  IN0 channel, wetting current start form A point, ADC or comp start work form where? A or B or middle?

Thank you,

Adam

  • 0
    TI__Mastermind 23653 points

    Hey Adam,

    The drawing in the figure indicates the time between enabling the current sources for each channel, set by Tadc or Tcomp. That is to say, the figure shows the waveforms you should expect to see and what spec corresponds with them NOT the internal timing or when the ADC/Comp are active. 

    As far as actual operation, the timing is described as follows:

    • During TPOLL_ACT, the current sources or sinks are enabled to bias the external switch.  They are on for the selected time to give enough time to charge up any external capacitors which may be in use.

    • Shortly before TPOLL_ACT is over, the comparator or ADC samples the voltage on the INx pin.  During this time, TPOLL_ACT is still high and the current sources/sinks are still active.

    • After TPOLL_ACT is over, the sample phase of the ADC or COMP is complete, and the current source is turned off. 

    • The ADC or comp then converts the data to the digital output when TPOLL_ACT is over.


    So to answer more directly about whether Tadc/Tcomp start at A, B, or somewhere in between the answer would be B, as the datasheet states:

    Hope this helps,
    Rami Mooti