I'm attempting to simulate the NE5234 op-amp via internal circuits. I'm not currently getting any errors, and so the AC sweep simulation does run, but I am getting 0 V on the output nodes. I'd appreciate any insight, or even a direction I should take to try to diagnose the issue.

Schematics of all stages with Volt Bias display ON.

The same schematics from the Analysis and Design of Analog Integrated Circuits text

Thanks for your help.

  • \$\begingroup\$ You are simulating open loop with one input to ground and the other one biased at 2.5V. Guess what... The out is saturated against 5V supply \$\endgroup\$
    – carloc
    Mar 24, 2019 at 15:40
  • \$\begingroup\$ Could you elaborate, on how I can go about changing that? \$\endgroup\$
    – Kluski
    Mar 24, 2019 at 16:07
  • \$\begingroup\$ Just close output to inverting input so to make a voltage follower. This doesn't mean the whole circuit itself is correct, at a glance it looks somewhat different from the one on your textbook \$\endgroup\$
    – carloc
    Mar 24, 2019 at 16:27

1 Answer 1


Looks like your Bias_1 and Bias_CM are open.

They need to to come from a current mirror BJT or at least be tied to (appropriate) voltage sources to turn the other parts of the mirrors on.


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