VDRIVE with external regulator
Hi. I am designing a product using an ADAU1452. I wish to use an external 1.2v LDO regulator for the DVDD supply. On page 192 of the datasheet is says in this case I can leave the VDRIVE pin floating. But on page 41 is says VDRIVE should be grounded if using an external regulator. Which one is correct?
Audio Signal Processors
adau1452
Datasheet/Specs
vdrive
SigmaDSP Audio Processors
SigmaDSP
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Hello xtec,
Oh man!! Look at the revision history of the document and you will see the extensive changes I made in 2018! A lot of the changes revolved around the regulator circuit too! Oh, well, I tried to make it perfect...
To your question. In the end it is not a huge deal either way, floating or grounded. I prefer grounding and if I recall correctly that was added to the datasheet back in 2018 but I missed the note on page 192.
Look at the internal circuit shown here:
It shows the location of the VDRIVE pin and internally there is a PMOS device to ground. So grounding the pin will prevent any currents from flowing through the PMOS device from things like RF or other digital noise. This is why I had suggested to ground it.
Thanks for using the part and I hope it works well for you!
Dave T
Thanks for the quick reply Dave. In that case I'll ground the DVDD pin.
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