LM4766: Is there a minimum loop gain for this amplifier

D.J. Wiendels

Part Number: LM4766
Other Parts Discussed in Thread: LM3886,

I am familiair with the LM3886, it hat a minimum loop gain requirement of Au=10 for stabillity

I am exploring the posibillity to design a bridged compound amp with the LM4766, so i can freely choose the gain of the LM4766 itself.
Does this part require a minimum loop gain like the LM3886? It is mentioned in the LM3886 datasheet, but i cannot find anything on the subject
in the LM4766 Datasheet. I am not interrested iun other parts/solutions.

over 1 year ago

0 Jesse Ji over 1 year ago

TI__Mastermind 20541 points

hi DJ

can below content in the datasheet help you?

it descripted Av is larger than 15.5

tks

jess

0 D.J. Wiendels over 1 year ago in reply to Jesse Ji

Prodigy 10 points

This is the Av calculated for the given amp requirement in the example.
I Know this, and can calculate/set it to any gain.
In the LM3886 datasheet, page 21, second line, there is a demand for a Au>10 in general. The part is not suposed to operate with a closed loop gain les than 10, for stabillity reasons.
Is there a simular demand for the LM4766? In other words: is it unity gain stable? and if not, what's the minimum Au to be used?

Kind regards

D.J. Wiendels

0 Jesse Ji over 1 year ago in reply to D.J. Wiendels

TI__Mastermind 20541 points

hi, Wiendels

if datasheet has no this kind of expression, it should have no same limitation as LM3886.

tks

jesse

0 D.J. Wiendels over 1 year ago in reply to Jesse Ji

Prodigy 10 points

I'm still doubtfull. But since it is going to be a composit amp, I'll have to thoroughly test it anyway.

So I will build a prototype suitable for tweaking / testing.

Thanks for your effort,

D.J.

+1 D.J. Wiendels over 1 year ago in reply to D.J. Wiendels

Prodigy 10 points

Diving deeper,

https://www.apexanalog.com/resources/appnotes/an47u.pdf

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LM4766: Is there a minimum loop gain for this amplifier