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TMS320F28377D: F28377D: Reference design for a differential ADC input

jawe477
Intellectual 700 points

Part Number: TMS320F28377D
Other Parts Discussed in Thread: THS4551, LAUNCHXL-F28379D, THS4531

Hello Community,

is there a reference HW-design for a differential ADC input (F28377D) available?

Or can somebody give me a recommendation for a diffential op-amp?

Thanks in advance,

jan

  • 0
    TI__Guru 60865 points

    Hi Jan,

    This is going to be pretty dependent on your application requirements.  

    • What are you trying to interface to?
    • Is the input to the signal conditioning circuit single-ended or differential?
      • What is the raw input voltage range?
    • Do you already have voltage rails selected for your signal conditioning circuits?
    • How fast do you need the ADC to sample a given channel?
    • What is most important to your application? Performance, power, area, cost?

    I'm going to move this to the op-amp e2e forums; they should be able to help the most with selecting a circuit topology to drive the ADC and picking an appropriate amp. based on your requirements.  

    ----------------------------------------------

    Relevant ADC information:

    • Resolution: 16-bits
    • Sample rate: 1.1MSPS
    • Inputs: Fully Differential
      • Common mode requirement: (VREFHI/2) +/- 50mV
    • Input range: Typically 0 to 2.5V or 0 to 3.0V.
    • ADC internal switch resistance: 700 ohm
    • ADC S+H cap: 16.5pF
    • Minimum S+H: 320ns 
  • 0 in reply to Devin Cottier
    TI__Mastermind 23226 points

    DiffAmpADCdrive.TSCHi Jan,

    Here is an ADC drive circuit based on the THS4551, for which we have a Evaluation Model. It settles the ADC specified above below 1 LSB/2 in 241ns. It has an input range from -0.2V to 3.8V with a 5V supply.

    Best regards,

    Sean

  • 0
    Intellectual 700 points
    Hello,
    thank you for your replies ;-)

    @Devin:
    I'm starting with this Controller and I want to understand how the 16-Bit-ADC with differential input works. I don't have a real application yet.

    @Sean:
    Thank you, this circuit is helpfully.

    @all:
    Meanwhile I found a reference design on the TI-Board "LAUNCHXL-F28379D". There is a circuit using the diff. op-amp "THS4531".

    Best regards,
    Jan
  • 0 in reply to jawe477
    TI__Guru 60865 points

    Hi Jan,

    If you need a source that has low enough noise and distortion to see the difference between 12-bit and 16-bit check out this EVM:

  • 0 in reply to Devin Cottier
    Intellectual 700 points
    Thanks for your advice.
    Looks interesting.
    ;-)