AD768S Accuracy

 

I'm interested in using the AD768S in a space application, as I've had success with it in the past on a previous space mission.  This mission's requirements include -20 to 60 deg C environment, a +/-10V range, 12-bit monotonicity, <+/-0.1% FS (0.020V) linearity error, and <0.2% FS (0.040V) total error.  The SMD doesn't seem to include the offset and gain tempco's.  I'm assuming the regular datasheet values should be used. The competitor's part is a DAC121S101QML.  The datasheet gain error tempco for this part is given as 'typical'.  I don't know if absolute min/max numbers are available.  Can you provide a second opinion about whether or not the AD768S device (and/or DAC121S101QML) will meet the requirements stated, and provide a total error calculated?  Please assume 0 error for supporting circuitry and gain and offset errors initially zero'd out.  If I use the DAC121S101QML, I will use a 5V reference/supply, bipolar output connection and a following 2x gain stage.  Any comparisons you can make would be appreciated. Thank you. JPJ

 

 

  • 0
    •  Analog Employees 
    on Mar 3, 2016 7:09 PM

    Hi JPJ,

    Unfortunately, ADI cannot comment about the competitor's parts. What we can do is to look at our own part's characterization data so that we would be able to advise you.

    Based on the SMD, worst case would be:

    Offset:  0.4%FSR over 180°C = 0.00222%FSR/°C
    Gain: 2%FSR over 180°C = 0.0111%FSR/°C

    This is based on using the Gain and offset limit over temperature.


    Looking at characterization data on 30 samples and the average calculated temperature coefficients across the full temperature range were:


    Offset Channel A:   0.00032 %FSR/°C
    Gain Channel A:      -0.00092%FSR/°C

    Offset Channel B:   0.00033%FSR/°C
    Gain Channel B:      -0.00089%FSR/°C

    The readings based on the SMD limits would be worst case and the calculated temperature coefficients based on characterization data would be typical. It is believed that AD768S will not be close to the worst case numbers as shown by the calculated temperature coefficients.

    Regards,

    Mark

  • 0
    •  Analog Employees 
    on Aug 2, 2018 3:23 PM
    This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

    Thank you,
    EZ Admin