FAQ: How to convert the AD717x data output Code to equivalent analog input voltage?
As discussed in What is the data output coding format used in AD717x family? the ADCs operate in unipolar or bipolar coding modes.
When unipolar mode is selected the ADC output code for any analog input voltage applied to the analog inputs can be calculated using the following formula as:
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Code = (2^N × AIN)/VREF |
· where AIN is the applied differential input voltage · VREF is the reference applied to the ADC. · N = 24 (number of data output bits)
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Example: AIN = 1V, VREF=5V. The equivalent code in unipolar mode is
Code = (2^N × AIN)/VREF = (2^24 x 1V)/5V = 3355443
When bipolar mode is selected the ADC output code for any analog input voltage applied to the analog inputs can be calculated using the following formula as:
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Code = 2^ (N – 1) × [(AIN/VREF) + 1]
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· where AIN is the applied differential input voltage · VREF is the reference applied to the ADC. · N = 24 (number of data output bits)
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Example: AIN = 1V, VREF=5V. The equivalent code in bipolar mode is
Code = 2^ (N – 1) × [(AIN/VREF) + 1] = 2^ (24 – 1) × [(1V/5V) + 1] = 10066329