The XS1-A (analog) and XS1-U (USB and analog) devices contain an ADC. If I do not plan to use the ADC function, what should I do with the AVDD and ADC_INx pins on my schematic?
What to do with AVDD and ADC_INx pins when ADC not used Topic is solved
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infiniteimprobability
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infiniteimprobability Verified
- XCore Legend
- Posts: 1164
- Joined: Thu May 27, 2010 10:08 am
AVDD should be tied to 3v3 when the ADC is not in used. This can be VDDIO, which is nominally 3v3. No special decoupling is required on the AVDD pin if the ADC is not in use (note if it is being used, then either a filter or seperate supply should be used for AVDD because Vref is also taken from this pin).
The ADC_INx input pins may be left unconnected, but as with any high impedance input pin on an IC, it is safest to tie it to a known level. Either AVDD or GND is fine. This prevents it from acting as a potential antenna and noise source into the IC.
The ADC_INx input pins may be left unconnected, but as with any high impedance input pin on an IC, it is safest to tie it to a known level. Either AVDD or GND is fine. This prevents it from acting as a potential antenna and noise source into the IC.
Engineer at XMOS