#323 Discrepency between Ngspice and Xyce simulation
Issue created by
adrienluitot
Environment
OS: Ubuntu 24.04
Tools: Qucs 24.4.1
Simulator: Ngspice-44 and Xyce 7.8
Expected Behavior
Having similar simulation results between Xyce and Ngspice.
Actual Behavior
We are designing a simple LNA at 2.45GHz. Here is its schematic and some ngspice simulation results:
lna_and_ngspice
On the right we see the Re(Z11) is 47.047Ω (with Ngspice).
When I run the same design, with the same parameters/variables, and the same simulation, but with Xyce, I get these results:
results_xyce
The discrepancy is not negligible here, mostly for Re(Z11), almost 10% difference.
For other results, there is not such a discrepancy, for instance, gain is pretty similar: 15.531dB for Ngspice and 15.561dB for Xyce.
I don't know if the error comes from:
• Me (Xyce installation maybe ?)
• Ideal components (maybe Xyce and Ngspice treat R,L,C slightly differently -> I will soon try with IHP's real components)
• Discrepancy between IHP's Ngspice and Xyce models
• Something else
Steps to Reproduce the Problem
1. Create a schematic in Qucs
2. Simulate with Ngspice
3. Copy whole schematic (design, parameters, simulations)
4. Adapt to Xyce (include & plugin)
5. Simulate with Xyce
IHP-GmbH/IHP-Open-PDK