• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 47 subscribers
  • Views 685 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADS4149: Spec measurements

Rick Jones78
Intellectual 340 points
Part Number: ADS4149

Hi,

I need to test the ADS4149 for some specs, i.e. DNL, INL, gain and offset errors.  These parameters do not seem to appear on the user guides for the ADS4149EVM + TSW1405EVM. 

Is there a simple/quick way to test for these parameters? 

  • 0
    TI__Mastermind 20541 points
    Hi Rick,

    We are looking into your question. We will get back to you soon.

    Regards,
    Neeraj
  • 0
    TI__Intellectual 785 points

    Hi,

    On EVM, ADS4149 is AC coupled to the driver (transformer). So, to test INL or DNL you will need to apply a sine wave, collect and store time domain data and then post process it. You may use 'histogram based' method where you should first generate ideal histogram for codes you see in ADC's time domain data, then compare it against actual histogram of codes. You may readily find information on google related to this subject. The HSDC pro software doesn't support INL DNL computation as yet.

    To test gain error, you will need to connect a DC voltage source differentially across ADC's analog inputs while maintaining common mode voltage as 0.95V, sweep differential voltage and record output code's median value. You may then best fit a line on observed output code, see its gradient to find the DC gain error.

    To test offset error, you may simply short the P and M terminals of analog input to the VCM pin. Then median code in ADC's output represents the offset error.

    So:

    1. INL DNL test: Needs no modification on existing EVM, but needs post-processing of collected time domain data.

    2. DC Gain error: Needs modification on existing EVM to force differential DC voltage. Needs simple post-processing of time domain data.

    3. Offset error: Needs no modification on existing EVM. The median value of code displayed in HSDC pro itself represents offset error.

    Regards,

    Sourabh