DAC5675A: Power Sequencing

Tom Domanski24

Intellectual 2995 points

Other Parts Discussed in Thread: DAC5675A, DAC5675A-SP

Hi there,

Are there are power supply sequencing constraints on the DAC5675A?

Here is the request from a customer, verbatim:

We have a system condition where DVDD lags AVDD as they are not the “one” supply

the data sheet advertises in our system. This is so that AVDD has a higher degree of filtering.

I have searched the Data Sheet and Ap Notes for supply sequencing requirements, but

it seems they make the assumption everyone will use the same +3.3V supply.

Questions:

Are there any sequencing requirements between the two supply inputs during:

Power ON

Power OFF

Are there any sequence time limits?

Simultaneous +/- XXXnS

No time limit from DVDD to AVDD

Regards,

tom

over 8 years ago

0 Neeraj Gill over 8 years ago

TI__Mastermind 20541 points

Hi Tom,

DAC5675A has apdiodes between the analog and digital supplies. The absolute maximum spec in the datasheet for AVDD and DVDD should be update from (-3.6V to 3.6V) to +/-0.9V, which means the two supplies should come up at same time or should be brought up such that they do not exceed the -/+0.9V difference between the two supplies.

Regards,

Neeraj Gill

0 Tom Domanski24 over 8 years ago in reply to Neeraj Gill

TI__Intellectual 2995 points

Thank you Neeraj.

Do you know whether these apdiodes (anti-parallel diodes, I assume) are also in the SP version of this device? I am inclined to believe that they are there, but still I want to make sure.

tom

0 Wade Vonbergen over 8 years ago in reply to Tom Domanski24

TI__Guru 62930 points

Tom,
The DAC5675A-SP uses same design as the commercial version and will have the same diodes.
We will coordinate and update accordingly.
Regards,
Wade

0 Tom Domanski24 over 8 years ago in reply to Wade Vonbergen

TI__Intellectual 2995 points

Thank you Wade

Data converters

Data converters forum

DAC5675A: Power Sequencing