Hello everyone. I'm trying to use the OTA I designed as subcircuit in a bigger circuit but I keep getting this Ngspice small timestep error whenever I try to simulate the larger circuit. I simulated the OTA subcircuits separately and they are working well. Please I need insight on what the problem could be. I will attach the 3 Xschem file one for the main circuit(two_equations), the other two for each OTA subcircuits(FC_sym and gm_1_sym). Thank you. Slack Conversation

@Emmanuel Innocent please add also the .sym files of the above subcircuits

Okay. I've now attached them here.

@Emmanuel Innocent your simulation fails because you have multiple voltage sources on

vinp

and

vinn

. There are voltage sources at the top level and in each of the sub schematics. Remove subschematics voltage sources on

vinn

and

vinp

Thank you very much @Stefan Schippers. I'll remove the voltage sources subcircuit