DDC232: DDC232C VREF op-amp

Thomas Stegmeijer

Prodigy 95 points

Part Number: DDC232
Other Parts Discussed in Thread: OPA350, OPA328

Hello,

TI recommends to use an op-amp to buffer the reference voltage for the DDC232.

The OPA350 is suggested, are there better buffer amplifiers that you recommend that are newer devices?

Most important is a low offset drift and stability with high capacitive loads.

I can select one myself but maybe you have an idea which already have proven to be a good selection?

Regards,

Thomas

7 months ago

0 Eduardo Bartolome 7 months ago

TI__Expert 4670 points

Hi Thomas,

I am not familiar with this specific device reference driving but unless you have a strong reason to change it, I would strongly suggest sticking with the DS recommendation, including the overall decoupling network. I am pretty sure a lot of research went into that choice at the time of releasing the device, it has been proven over many customers, it is easy to discard as a culprit if something doesn't work later, etc.

Regards,
Eduardo

0 Thomas Stegmeijer 7 months ago in reply to Eduardo Bartolome

Prodigy 95 points

I want to stick with the principle of the DS of having a reference and buffering it. But since the OPA350UA is already an older design I want to reconsider the op-amp choice. Also because our design needs to be able to be made for another 15 years.

0 Eduardo Bartolome 7 months ago in reply to Thomas Stegmeijer

TI__Expert 4670 points

Ah, I see your reasons... May want to check with that team (OPA team) but TI has a pretty strict obsolescence policy, so, production may go easily till that time... Anyhow, the same team can otherwise recommend something but we haven't tried it, so, you would have to do the checks...

Let me see if I can get someone to move the thread to that team or reply here... or you can just try posting there...

0 Michael Hartshorne 7 months ago in reply to Eduardo Bartolome

TI__Genius 12215 points

Hi Thomas,

The OPA328 is our next generation that we would recommend here. We have an app. note where the analysis for the large capacitor + series resistance was done, similar to the recommended circuit in the DDC232 app. note:

https://www.ti.com/lit/an/sboa558/sboa558.pdf

Please look this over and let us know if there's any questions.

Regards,
Mike

0 Thomas Stegmeijer 7 months ago in reply to Michael Hartshorne

Prodigy 95 points

Thank you for the app note!

Will have a look at that and see if we can use the OPA328.

Data converters

Data converters forum

DDC232: DDC232C VREF op-amp