About voltage of external regulator at ADAU1452W
Thread Summary
The user inquires about the configuration of DVDD for the ADAU1452W, specifically if using 1.8V for the external PNP transistor while VDDIO is 3.3V is acceptable. The support engineer confirms this configuration can cause a supply sequencing issue, potentially damaging the ADAU1452, unless 3.3V is brought up before or simultaneously with 1.8V, and 3.3V is brought down after or simultaneously with 1.8V.AI Generated Content
Dear support team,
I have a question about configuration of power for DVDD at ADAU1452W.
Q.Is below configuration of DVDD acceptable?
VDDIO = 3.3V
External PNP transistor input = 1.8V
I explained it in PPT file(Power_config_for_adau1452_140210.pptx).
Best regards,
Takepiro
There is a supply sequencing issue if we try to use 1.8 V for the external PNP while IOVDD = 3.3 V.
For either start-up or power-down, if the 1.8 V supply is up while the 3.3 V supply is down at ground, then the external PNP acts as a switch, passing 1.8 V onto DVDD, which will damage the ADAU1452.
This can be avoided if you can ensure that 3.3 V will come up before or at the same time as 1.8 V, and that 3.3 V will go down simultaneous or after 1.8V goes down.
Dear Brett-san,
Thank you very much for your supports.
Best regards,
Takepiro
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