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ADS1148 / Gain error drift, Offset error drift figure

Ryuji
Guru 20090 points
Other Parts Discussed in Thread: ADS1148, ADS1248
Hello,
 
Concerning ADS1148 there are offset error drift and Gain error drift in data sheet Page 3.
But there is not curve of its.
Could you please kindly let me know the curve of offset error drift and gain error drift , if I can get?
 
It is OK for 25°C~35°C data in both.
 
I think that this data comes from BOX method.
So there may not curve too.
But, please let me know if there is any data.
 
Best Regards,
Ryuji Asaka
 
  • 0
    TI__Guru** 113765 points

    Hi Ryuji,

    It is not hard to create your own graph in a spreadsheet program.  As the initial gain error is +/- 0.5%, you need to create a graph showing the range of error over the temperature range you will be operating.  Remember that the amount of error is also dependent on gain.  The Total Error is the RSS (root sum square) of all the individual error sources.  Gain error tends to be the dominant error source.

    Best regards,

    Bob B

  • 0 in reply to Bob Benjamin
    Guru 20090 points
    Hello Bob san,
     
    Thank you.
    I understand that gain error drift and offset error drift has linearity.
    Is my understanding correct ?
     
     
    By the way, could I have gain error and offset error drift at the condition of PGA=32?
     
    My customer may use PGA=32 and Ta=30°C.
    So, I would like to know PGA=32 data.
    Then, I will create 25°C~35°C graph.
     
    Best Regards,
    Ryuji Asaka
     
     
     
     
     
     

     

  • 0 in reply to Ryuji
    TI__Guru** 113765 points

    Asaka-san,

    It is not always a straight line response.  About the best way to show you is by looking at the ADS1248 datasheet to see the characteristic plots for data across temperature for offset and gain at various data rates.  For the ADS1148 the drift becomes less significant as it is 16 bit compared to 24 bit.

    Best regards,

    Bob B

  • 0 in reply to Bob Benjamin
    Guru 20090 points
    Hello Bob sam

    Thank you for the informaiton.
    I can see the ADS1248 drift data.
    I informed that ADS1248's drift data as refference data of ADS1148 to my customer.
     
    Best Regards,
    Ryuji Asaka