AD7665 Start up sequency OVDD DVDD AVDD

Document created by analog-archivist Employee on Feb 23, 2016
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According to the datasheet, the power up sequencing is no problem as long as
the default:
DVDD >/= OVDD - complies with 0.3V

In my case, AVDD and OVDD are connected together because they are equal.
How critical is this?

 

OVDD cannot exceed DVDD by more than 0.3V during power up.

This may be an issue if AVDD and OVDD are connected together as DVDD will come
up slower and OVDD could possibly exceed DVDD by 0.3V.

I don’t think it’s a good idea to connect AVDD and OVDD together as digital IO
noise on OVDD will couple into the analog supply. Can you connect DVDD and OVDD
together? This would be an alternative.

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