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ADC121S101-Q1: Offset and accuracy queries

Naveen Bevara
Intellectual 1970 points
Part Number: ADC121S101-Q1

Hi Team, 

Operating conditions of customer's application:

  • Operating Temperature: -40 deg C to 125 deg C
  • Reference Voltage Tolerance: 4.994V(min); 5V(typ); 5.006V(max)
  • 12 Bit ADC
  • VA is considered same as Voltage reference

 Consideration done for the Worst case calculation and accuracy:

  • DNL error : 1LSB (max)
  • INL error : 1LSB (max)
  • Offset error: 1.2 LSB(max)
  • Gain error : 1.2LSB (max)
  • Error due to Voltage ref.

 Can you please suggest on below questions:

  • I did not find any offset drift and gain drift error from the datasheet so can you please let me know if those values to be considered for accuracy calculation based on all conditions or whatever errors considered is fine?
  • W.R.T the operating conditions mentioned above is it necessary to consider the maximum DNL, INL and other errors or if typical is OK for our application.
  • Will conversion Noise affects the accuracy?

Regards,
Naveen

  • +1
    TI__Mastermind 24970 points

    Hello,

    This device was released almost two decades ago, and specifications for devices have since changed, thus drift information is not readily available for this device, also note that this device was art of an acquisition which would make it that much more difficult t find any data, if available. . Because it is an Q1 device, the device is expected to maintain performance across the temperature. 

    Based on the specifications you are looking at, I am assuming that the input signals are DC. Maximum and minimums calculations should be used to maintain performance of a system within requirements, but should not be used for direct designs, as it is not common for device to operate at these extrema's

    There is a great blog series on this topic, in particular, Part 2: Total Unadjusted Error,

    Regards

    Cynthia