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tms320c5505: +vref and -vref for on chip adc of tms320c5505

Kanchan
Expert 1445 points
Part Number: TMS320C5505
Other Parts Discussed in Thread: TMS320C5505

dear sir,

can u plz tell me what is the +vref and -vref  for on chip adc of tms320c5505..??

  • 0
    TI__Guru**** 161600 points

    Hi,

    The datasheet states:
    The device SAR supports the following features:
      - Internal configurable bandgap reference voltages of 1 V or 0.8 V; or external Vref of VDDA_ANA

    So my understanding is that VDDA_ANA can have either 1V or 0.8V internal bandgap reference or external Vref. My understanding is that the Vref should be the same as the internal configurable bandgap reference voltage: 1V or 0.8V. But this may depend on your design.


    See the following threads for additional information:
     

     

    Also have a look at the ADC User Guide:
     

    Search for "reference voltage"


    Best Regards,
    Yordan

  • 0 in reply to Yordan Kovachev
    Expert 1445 points
    thanks yordan,
    u mean i can set the input waveform of (+0.4vto -0.4v )or(-0.5v to +0.5v) for converting continuous sine wave to the digital samples...m i right or i need to clamp it to 1v or 0.8v
  • 0 in reply to Kanchan
    TI__Guru**** 161600 points
    I don't think you should clamp the input.
    Here is how the ADC takes samples:
    num_of_samples = (Vin/Vref) x 1024

    Where Vin is the input. You still have to set Vref (it can either be internal or external).

    Best Regards,
    Yordan
  • 0 in reply to Yordan Kovachev
    Expert 1445 points
    thanks a lot