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ADS1283: PGA input noise is is much higher than datasheet typical value

Harson
Expert 3700 points
Part Number: ADS1283

Hi, Team

My customer DTCC has concern about ADS1283 PGA noise in datasheet.

In Table 1, there are RMS noise value with CHOP ENABLE. DTCC measured that there are 1 of 20 samples which has higher than the value in the table.

They compared that the measured input noise uV with datasheet value. SI(ms) means the sampling interval, which is equal to 4Ksps, 2Ksps, 1Ksps, 500SPS, 250SPS.

The yellow value is higher than datasheet value.

1   I'd like to double confirm with you that this is a typical RMS noise value that we listed, it's not the maximum that we screen out from ATE.

2   Is there a maximum value that we can tell customer for this table? So I can convince them that it's in our maximum limit.

  • 0
    TI__Mastermind 44680 points
    Hi Harson,

    You are correct, the datasheet noise values are typical specifications. From the above results it looks like your customer is getting pretty close to datasheet results; therefore, I wouldn't be too concerned.

    There may also be some slight differences in the test conditions that might be able to account for the additional RMS noise. For example, how close to the ADC the input signals are shorted (i.e. a larger loop area may pickup more noise) and how much data is collected (i.e. longer sampling results in more time for drift errors to affect the RMS calculation) may affect the noise performance. I notice that most differences between the customer results and the datasheet figures occur at the slower data rates, so perhaps decreasing the number of samples collected (to keep the total sampling time consistent for all data rates) might cause results to improve.

    I do not have data to be able to say the the maximum RMS noise would be. The noise performance will also be somewhat system dependent, as the noise can be affected by layout, supply noise, and environment noise (for example).

    Best regards,
    Chris