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ADS8866: ADC CHARACTERIZATION

saikumar A
Prodigy 100 points
Part Number: ADS8866
Other Parts Discussed in Thread: DAC9881EVM, , DAC9881

Tool/software:

Subject: Query on Selecting and Testing 16-bit ADC (ADS8866EVM) Using DAC9881EVM

Hello TI Team,

I'm currently working on an application that requires accurate measurement using a 16-bit ADC. To evaluate the ADC performance and suitability, I shortlisted ADS8866EVM for initial characterization.

I would like to know:

  • Is ADS8866 a good choice among 16-bit SAR ADCs from TI for general-purpose precision measurement?
  • Are there any alternative 16-bit ADCs from TI that offer better performance (INL/DNL, noise, speed, etc.) or have easier integration features?

For testing and characterization, I plan to use DAC9881EVM as the precision voltage source input to the ADC.

  • Is DAC9881EVM a suitable choice for providing input to ADS8866EVM during evaluation?
  • Do you recommend any better DAC for this purpose in terms of low noise, linearity, or compatibility?

I’m aiming for a setup that gives reliable insight into the true performance of the ADC without being limited by the DAC performance.

Looking forward to your guidance and suggestions.

Thanks & regards,

Saikumar A

  • 0
    TI__Expert 8545 points

    Hi Saikumar, 

    Thanks for your question. We do have faster ADCs than the ADS8866, but I'd like to learn more about your application before offering recommendations to ensure your requirements are met. Could you help with the following:

    1. What kind of application do you plan to use this ADC in?
    2. What max sampling speed are you looking for?
    3. What is your input signal voltage range?
    4. ADS8866 is a very low power, no frills added device. Would you like integrated features like front-end programmable gain amplifiers to set different input voltage ranges? Or internal reference option?
    5. Is 1 channel sufficient or would you like a multi-channel device (like 4/8/16 channels)?

    Let me loop in the DAC team regarding the DAC question.

    Also, looks like there is a duplicate post, so I will delete that one.

    Best regards,

    Samiha

  • 0 in reply to Samiha Sharif
    Prodigy 20 points

    Hi Samiha,

    Thanks for the response.

    Actually this is not for a specific end application, but rather for evaluation and characterization ADC performance by sweeping the input using DAC9881.

    We have to test 16bit ADC performance from different vendor in upcoming weeks, so for strong understanding we take this ADS8866 for characterization.

    low speed is fine, and no extra features like PGA are required, and voltage range will be up to 5V.

    Just confirming will this DAC9881 output drive capability, output impedance and settling time will be adequate for ADS8866 input requirements?

    Any concern about the ADC acquisition time affecting accuracy when directly driven from DAC9881?

    If this combination not suitable, could you suggest a TI EVM combination for evaluating a single Channel ADC with 0 to 5V input range and without extra amplifiers in the signal path.

    Thanks,

    Saikumar A

  • 0 in reply to saikumar A
    TI__Expert 8545 points

    Hi Saikumar,

    Thanks. In that case, ADS8866 should be sufficient. I will let the DAC team comment on the DAC.

    Best regards,

    Samiha

  • 0 in reply to Samiha Sharif
    TI__Guru* 97415 points

    Saikumar,


    I think the DAC9881 should be fine to drive the ADC. The DAC9881 uses an output buffer that has an output drive of about 2.5mA. The output impedance should be extremely low because the buffer feedback allows for a force/sense connection to the load. The settling time of the output is dominated by the output slew rate of the buffer. The settling should be approximately 5us with a slwe rate of about 2.5V/us.


    Joseph Wu