AD7608 resolution question

Hi. 

I am using AD7608.
ADC7608 resolution is 18bit. so when i used in the range of +10 ~ -10 I know that 1bit is 76.29uV.
20V / 262,143 (18 bits) = 76.29 uV
Is there a software technique that can express 1uV using the ADC7608? Calibration algorithm, average, etc.
Thanks.
  • 0
    •  Analog Employees 
    •  Super User 
    on May 19, 2019 10:50 PM

    HyuckJoo,

    If you are looking for 1uV of resolution then yes you can use averaging, however to obtain 1 uV your are going to have to average over 5000 samples.   Remember, doing so will reduce your overall measurement bandwidth. 

    If you require a large dynamic range you may be better off using multiple channels to monitor the same signal.  The first channel would be driven with a buffer (or small gain depending on signal amplitude) and would monitor the input when the signal is large.   The second channel would be configured with a gain say of 32 or 64 (30 or 36dB) and would monitor the same signal when the input is below 1/32 or 1/64th of the input range.  You can then use oversampling/averaging of both outputs to reduce any additional noise introduced into your measurement by the noise gain of the input signal conditioning.

    BR,

    sk