TLA2528: DVDD powered with no AVDD

Mark Guastaferro

Part Number: TLA2528

Customer has a condition where the DVDD pin will be powered with 1.8V, but AVDD is not yet powered. Is this a concern for the TLA2528?

Note that the Ain inputs are not present during this condition so the inputs are not > AVDD. AVDD is normally 3.3V when powered.

6 months ago

0 Tom Hendrick 6 months ago

TI__Guru**** 172836 points

Hi Mark,

Take a look at the ABS MAX table on page 4, section 6.1. There are no restrictions on AVdd versus DVdd so that lets you know that there are no sequencing issues. The only restriction is for the inputs WRT AVdd. So there are no concerns with DVdd on and AIN/AVdd off.

0 Mark Guastaferro 5 months ago in reply to Tom Hendrick

TI__Genius 11235 points

Hi Tom,

I need to revisit this question. Is there a possible leakage path between DVDD and AVDD? The customer reports that when DVDD is powered (1.8V) but AVDD (3.3V) is not, they think there is current feeding the AVDD pin from the DVDD supply. I don't yet have details on the voltage or current they see at the AVDD pin, but wanted to check if this is possible with the TLA2528. They are thinking of placing a diode in the AVDD path to block reverse current.

0 Tom Hendrick 5 months ago in reply to Mark Guastaferro

TI__Guru**** 172836 points

Hi Mark,

There is nothing that I'm aware of.

0 Tom Hendrick 5 months ago in reply to Tom Hendrick

TI__Guru**** 172836 points

See if you can get a little more detail, and maybe share a schematic if possible.

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TLA2528: DVDD powered with no AVDD