I have problem with ad7763. After designing PCB according with datasheet, I have only 14 noise free bits (measured with shorted inputs). Is it normal for this ic ?
I would like to ask about the settings you have on the AD7763. At what decimation rate was it set and have you use digital filter on it and what is MCLK speed?
By the way when you say that the inputs are shorted, what does it mean, are they shorted together and at the same time shorted to ground or both pins are only shorted together. If it is okay, please share the schematic showing the connections of the pins and how it is set up in your application. Can you also show how you arrived with the 14 bits?
You can also refer to this link for your reference in computing the noise free bits.
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