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MSPM0G1507: Sampling time relationship to OPA gain

Robert Finger
Genius 17367 points
Part Number: MSPM0G1507

Team, 

The datasheet shows that the sampling time changes when the OPA or GPAMP is used as input. 

  • The values with OPA, have they been measured or where do they come from? I don't see a direct relation between GBW, gain and sampling time. 
  • Do we have a more detailed graph, showing how sampling time relates to OPA gain?

Thanks,
  Robert

  • 0
    TI__Genius 10611 points

    Hi Robert,

    Thanks for your question.

    We will have a discussion internally and give you answer later.

    B.R.

    Zoey

  • 0 in reply to Zoey Wei
    TI__Genius 10611 points

    Hi Robert,

    1. The values with OPA, have they been measured or where do they come from? I don't see a direct relation between GBW, gain and sampling time. 

      -> Our team are measured from silicon. Sampling time is inversely proportional to GBW(lower sample time for GBW=1 than GBW=0) and directly proportional to gain. As we increase gain from G=1 to 32, GBW falls proportionally and hence sample time increases.

    2. Do we have a more detailed graph, showing how sampling time relates to OPA gain?

    ->Settling time of OPA via ADC vs gain of OPA:

  • 0 in reply to Zoey Wei
    Prodigy 10 points

    Hi Zoey,

    Thanks for this reply. I do have some more questions:

    1. Are these typical values or worst case?
    2. Is this data true for both G and L series?
    3. Will this data be present in MSPM0 datasheet?
  • 0 in reply to Lukasz Matuszak
    TI__Genius 10611 points

    Hi 

    Here is our design & system team answer.

    1.Are these typical values or worst case?
    These are worst case values. Worst Case is observed at Temp=130degC, LOT(Process)=HOTCOLD.
    2. Is this data true for both G and L series?
    This data is collected for G series. Similar kind of settling performance is expected in L series.
    3. Will this data be present in MSPM0 datasheet?

    Data present in datasheet is across P,V,T and hence not exactly same as plotted for this one device.

    NB: We have done complete char at all corner (Process, Voltage, Temp) for Gain=1 and Gain =32 which is specified in datasheet.

    B.R.

    Zoey