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ADS1014: Need to calculate the Sample and hold error of the IC

Rajat Jhunjhunwala
Prodigy 110 points
Part Number: ADS1014

Hello, 

Kindly help me out to understand the formula for the sample and hold error calculation for ADS1014 IC. Input is a analog signal (0 - 5V) and Vcc= 5V. 
It is necessary to for final ADC error calculations. 

Kindly help me to understand the CA1, CA2 and CB values of internal sampling capacitors. 

Regards,

  • 0
    TI__Mastermind 31655 points

    Hello Rajat,

    To better answer, it's important to first understand the way the Delta Sigma ADC produces conversions. Each sample is passed into a single bit ADC which compares the sampled voltage to a threshold and outputs a 1 or a 0. This bitstream of data is passed through a filter that essentially averages these 1 bit conversions into the full output at a slower rate based on the oversampling ratio (this is what is set when you configure the data rate). Because each sample ends up being a single bit conversion, any sample error is averaged out and basically becomes part of the offset error that is described in the datasheet specification tables and shown in figures 4 and 5 across temperature. 

    Regards,

  • 0 in reply to Scott Cummins
    Prodigy 110 points

    Thankyou for the reply Scott. Can I confirm that there is no separate sample and hold error and no conversion error as well in the conversion procedure but included in offset error itself?

    Kindly help me on this. Thanks

  • 0 in reply to Rajat Jhunjhunwala
    TI__Mastermind 31655 points

    Hello Rajat,

    Yes, potential sources of error are included in the System Performance section of the datasheet specifications. The offset error includes what would essentially equate to the sample and hold error you mention.

    Regards,