Chips & Tech.

Thursday, October 30, 2025

Some simple discrete transistor Op Amps

The problem with Op amp and other iC.-s models dev. is that you always miss to conduct a "critical test" . . . that , untill you make it and find out the next flaw . . . coz at the time you only need it to perform certain tasks at certain env. . . .

The first Amp -- it's quite old stuff . . . is the only simulation i found and was able to set to work . . . reasonably near to what you'd expcect it should !?

UPDATE ! -- extended supply - but it's likely a poor op amp compred to the number of transistors used for it
however -- now it !looks! quite decent up to gain 5x ??? ▼

The second Amp

[EoP]

Tuesday, May 24, 2022

Evaluating my CLM-s Transistor-/Component- Level models for LM321/358/324

Update : The predecessors of the below - the internals of the LM324 equivalent circuits are irrelevant - the purpose here is to provide a multitude of random ways to make the models to show up their weak spots

®-lly oriented for +5(±2.5)V Vs (!Only) - now up to ±15V "verification"

TEST.1

TEST.2

Update.2 ::

TEST.3

TEST.4

Note : the Test.4 is slow ramping , pos.-feedback oscillator -- usually the very fast or very slow ramps do trigger instabilities in the voltage comparators and in some op amp.-s (notice , that the previous tests didn't reveal any serious "bugs" /!\) . . . here we got 3 failed (unstable) , 3 - poor (it's "unexpectedly") , 1 strange (a macro-) model ... and 1 decent simulation model (!!! but not an exact functional analog of the LM321)

Links :

https://zeptobars.com/en/read/TI-LM358-dual-general-purpose-opamp

https://zeptobars.com/en/read/Ti-LM324A-LM324-quad-opamp

[Eop]