sheldon
|
Simon,
First to make sure I understand your approach, you are using 6 test benches to measure six parameters effectively. In one test bench you measure the offset voltage and pass it to another test bench to cancel the offset voltage so the output is not saturated when you measure the open loop gain.
Some comments, 1. Usually for an op amp one test bench is sufficient. You can measure many parameters from a single test bench for an op amp. 2. In general, the method you are using to measure the open loop gain is not recommended. There is a good treatment of the topic in Ken Kundert's book, "The Designer's Guide to SPICE & Spectre", Chapter 3. Technically these really focus on loop gain. 3. The simplest method is to measure the open loop gain in your closed loop test bench, vac(out)/(vac(ii_noninverting)-vac(inverting).
Sheldon
|