Summing Amplifier with non-ideal op-amp

[Jim Thompson]

John Popelish on Mar 9, 10:20 am wrote:


So could this ever be considered a legitimate technique for gain /
slew-rate adjustment? Or is it just too stupid?

Doing any adjustment that relies on OpAmp parametrics, and them
staying stable, is plain IGNORANT.

...Jim Thompson

 

[Jim Thompson]

Putting shunt elements across the two inputs is a sometimes used
method to improve/alter the stability of an opamp, by changing its
effective open loop gain and phase response. I have seen it used to
turn a comparator into an opamp. It doesn't affect the slew rate,
which doesn't involve the input gain stage.

Which reminds me... sometimes bypassing the summing node to ground can
improve system noise problems.

...Jim Thompson

 

[John Popelish]

John Popelish on Mar 9, 10:20 am wrote:

So could this ever be considered a legitimate technique for gain /
slew-rate adjustment? Or is it just too stupid?

Putting shunt elements across the two inputs is a sometimes used
method to improve/alter the stability of an opamp, by changing its
effective open loop gain and phase response. I have seen it used to
turn a comparator into an opamp. It doesn't affect the slew rate,
which doesn't involve the input gain stage.

 

[Guest]

Which reminds me... sometimes bypassing the summing node to ground can
improve system noise problems.

...Jim Thompson

When you "improve a problem" do you make it better or worse?

Jim

 

[Jim Thompson]

When you "improve a problem" do you make it better or worse?

Jim

Depends ;-)

...Jim Thompson

 

[John Woodgate]

I read in sci.electronics.design that [email protected] wrote (in

When you "improve a problem" do you make it better or worse?

Neither; the words are orthogonal.

 

[John Larkin]

I read in sci.electronics.design that [email protected] wrote (in


Neither; the words are orthogonal.

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Holy Moley, he's right!

John