LM4040C25-EP: Using LM404 in op-amp feedback loop

JIM BRENTANO

Prodigy 65 points

Part Number: LM4040C25-EP
Other Parts Discussed in Thread: LM4040, LM4040-N

Tool/software:

Can the LM4040 be used in the feedback loop of an op-amp to limit the output voltage swing?

over 1 year ago

0 Jackson Wightman over 1 year ago

TI__Expert 8730 points

Hi Jim,

There is nothing inherently wrong with placing LM4040 in the feedback loop of an op-amp as long as the current ratings of the device are met. Are you wanting to replace a Zener diode with LM4040?

Thanks,

Jackson

0 JIM BRENTANO over 1 year ago in reply to Jackson Wightman

Prodigy 65 points

Hi Jackson,

Yes, that is correct. I am looking to provide some AGC on an oscillator and need it to be stable over temp. I plan on using two LM4040 in series (anode to anode) in the feedback loop. I believe I will have the Vf of one of the diodes to contend with over temp.

Thanks,

Jim

0 Jackson Wightman over 1 year ago in reply to JIM BRENTANO

TI__Expert 8730 points

Hi Jim,

Got it. If the min and max cathode current values that are expressed in the datasheet are met, I would expect using LM4040 in the feedback loop to be no problem. The LM4040-N datasheet does include an example of this application on page 43, if that is helpful.

https://www.ti.com/lit/ds/symlink/lm4040-n.pdf

Thanks,

Jackson

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LM4040C25-EP: Using LM404 in op-amp feedback loop