opamp simulation

[promach]

For the Improvements_in_biasing_and_compensation_of_CMOS_opamp (second reference link), why the author break open the connection between gates of M3A and M3B ?

And how to derive the inequality expression (14) in the document ?

[Wimberleytech]

For the Improvements_in_biasing_and_compensation_of_CMOS_opamp (second reference link), why the author break open the connection between gates of M3A and M3B ?

And how to derive the inequality expression (14) in the document ?

Set P3 < P1 and simply do the algebra.
Eq 14 appears to have an error...should be gm2b in numerator, not gm2a

[promach]

Set P3 < P1 and simply do the algebra.
Eq 14 appears to have an error...should be gm2b in numerator, not gm2a

I will check your advice regarding the inequality expression, but why set P3 < P1 ? Is it dominant pole compensation or something else ?

I try to incorporate the author schematics (Figure 6 in the second reference link) into the opamp, but it resulted in erroneous bode plot

Which part is wrong in the schematics ?

[Wimberleytech]

Set P3 < P1 and simply do the algebra.
Eq 14 appears to have an error...should be gm2b in numerator, not gm2a

I will check your advice regarding the inequality expression, but why set P3 < P1 ? Is it dominant pole compensation or something else ?

yes, essentially

I try to incorporate the author schematics (Figure 6 in the second reference link) into the opamp, but it resulted in erroneous bode plot

Which part is wrong in the schematics ?

ALWAYS check bias points before even looking at your ac response.  In this case, your biasing is broken. 

[promach]

See the following circuit :

I am having problem using the miller lead compensation (M24 mosfet in triode region)

Any help ?

When I saw this 90MHz bandwidth opamp OPA838, I am inspired to do the same, but my current circuit bandwidth is only 10MHz.

[promach]

I managed to obtain unity-gain bandwidth = 275MHz , phase margin = 76 degrees , Gain = 93 dB , Power dissipation = 366 uW

[promach]

Set P3 < P1 and simply do the algebra.
Eq 14 appears to have an error...should be gm2b in numerator, not gm2a

Wait, I tried setting P3 < P1 , but I am getting totally different result from expression 14.

I think you have wrong interpretation of expression 14 ?