OpAmp differential voltage range ?

Oct 14, 2008 2 Replies
H

I thought I found an ideal micro power OpAmp for another low power LDO I'm building in the LMV641. Small offset, RR output, 10MHz GBW, 2.6 V/us and still pretty good drive capability +/- 20mA.



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There's one thing I'm concerned about it specs a max differential input of +/- 0.3V. Under normal operation this shouldn't be a problem but at start up and shutdown this may be exceeded. Is this likely to hurt the reliability of OpAmp? Should I place current limiting resistors on both opamp's inputs?



Schematic



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J

Many opamps have clamp diodes between their inputs. A few mA of transient current won't do any harm. Your circuit looks OK as-is.

Incidentally, your circuit is backwards. Convention is input on the left, output on the right.

John

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H

Thanks John.

This is the first LDO I've built that actual performs identically to the spice simulation.

Guilty as charged. I don't know why I do that sometimes. If you look in the bottom right corner you'll see I stuck with convention for my

1/Beta schematic. Input to the left.;)
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