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ADC12DJ3200: difference between the analog inputs

Ingo Kraemer
Prodigy 20 points
Part Number: ADC12DJ3200

We want to interleave two of the ADC12dj3200. When you place two ADC's beside each other INB+/- of the upper ADC and INA+/- of the lower ADC are closeby. So it would be easier to interleave these inputs. But if INA and INB are not very similar the performance of the interleaved system will be bad.

In section 7.1 (page 38) of the data sheet  is written that "performance has been optimized for INA+/-" (data sheet  version: June 2017).

What is the exact difference between the analog Inputs INA+/- and INB+/-. Are they different in gain response or phase response? How big is the difference?

  • 0
    TI__Mastermind 44680 points

    Hi Ingo

    Factory trimming is done to optimize the internal interleaving performance (gain, sample timing matching, etc.) for the single input mode. These trim settings are optimized for the INA+/- signal path. If the INB+/- path is selected the interleaving spur performance will be degraded due to higher gain and timing mismatch than for INA.

    The gain and timing adjustment registers are auto-loaded on power-up with the factor trim values, but can then be adjusted by the user if desired. This would allow a user to implement their own trimming process for the INB+/- input, but the procedure would require a known test input signal and must be done on each ADC in the system. The resulting new trim values would need to be stored in the customer system and reloaded to the respective ADCs every time they are powered up.

    Best regards,

    Jim B