CMRR simulation in hspice

[waosai]

Hi, I'm using hspice to simulate the CMRR of opamp. The method I used is from P.E.Allen's book. The configuration is shown in the picture.



The difference is I used two vcvs to replace the original independant source. I think this is equivalent. But when I run it, hspice said "**error** inductor/voltage source loop found ...". I think it must come from the input "vi” and the two vcvs.
But I can't figure it out.

Anybody can tell me where the problem is? Thanks!

 

[keith1200rs]

But when I run it, hspice said "**error** inductor/voltage source loop found ...". I think it must come from the input "vi” and the two vcvs.
But I can't figure it out.

Anybody can tell me where the problem is? Thanks!

That error is often caused when your circuit can create infinite current. In your case a voltage source feeding a voltage source. Putting a tiny resistor between them should solve it. 1milli ohm for example.

Keith.