AMC1304Lxx : can LDO ouput (VCAP) be used to supply an opamp?

Robert Ganter

Other Parts Discussed in Thread: AMC1304L05, OPA376, AMC1304L25

Hello,

I am evaluating the AMC1304L05 and AMC1304L25. Application report SBAA215 describes a possible solution to optimize offset and gain errors using an opamp at the input (OPA376 in this case).

This opamp consumes <1mA and is specified for a 2.2 to 5.5V supply voltage. As the AMC1304Lxx LDO output (VCAP) is 3.45V it would be nice to use it also to supply the opamp. Is this possible and recommended by TI?

Thanks in advance for You help

Robert

over 7 years ago

0 Tom Hendrick over 7 years ago

TI__Guru**** 168485 points

Hi Robert,

Welcome to the e2e forum! Let me see if I can get some detail on what current levels can be provided from the LDO output on the AMC1304. I'll get back with you as soon as I can get some information.

0 Tom Hendrick over 7 years ago

TI__Guru**** 168485 points

Hi Robert!

I am sorry for the delay in getting back to you but the people I need to confer with are out of the office on business travel. I hope to have an answer for you by Monday the 31st.

0 Tom Hendrick over 7 years ago

TI__Guru**** 168485 points

Hi again Robert,

My apologies again for the delay on this query, but we have not characterized the loading of the LDO output from the AMC1304L05 or AMC1304L25 for anything more than the AMC1304 itself. While it might be possible to power the OPA376 from the AMC1304, we don't have the data to recommend this as a viable option under all possible operating conditions for your power rail needs. I would recommend looking into a stand alone LDO to power the OPA376.

0 Robert Ganter over 7 years ago in reply to Tom Hendrick

Prodigy 110 points

Hi Tom,

now it's up to me to apologize for the delay...

Thanks for Your answer. We have decided to use a dedicated isolating DC/DC converter to power the isolated side of the AMC1304.

Best regards

Robert

0 Tom Hendrick over 7 years ago in reply to Robert Ganter

TI__Guru**** 168485 points

Cool! Happy Holidays to you and your family!

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AMC1304Lxx : can LDO ouput (VCAP) be used to supply an opamp?