Please teach me about unused pins of AD9681.
All the ADC input is not used.
How should I process an unused pin(VIN+/- pin)?
If you have SPI communication with the AD9681, the best thing to do would be to power-down the unused channels. This can be accomplished by writes to Register 0x05 and Register 0x22. With the channel powered down, you can just leave the analog input pins unconnected (floating).
If you do not have SPI control, there are several options.
If you know which channels you would like to power down, please let me know and I can send you the SPI register write sequence.
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