Hi Diarmuid, we just told about new capabilities of IHP PDK for statistical simulation. I confused something: New (since March 26) is the feature to make MC global + local simulation with resistors. The entry is named res_stat_mismatch. For transistors we have only the shown corner + mismatch entries. Question is: How important is this feature for this kind of projects as yours? KR Dietmar Am Di., 17. März 2026 um 18:32 Uhr schrieb dick freebird dfreebird@users.sourceforge.net: Easiest way would...
Extracted circuits with not proper layout or insufficient extraction setup contain often ton´s of dangling capacitors. I could sing a song about ...
Not in a circuit description, but a equivalent case: We are using a voltage source in VDMOS thermal model to apply ckt temperature to the case node. It is direct stamped into the model MNA stamp together with a series resistor RTHCA. This branch is often in parallel to an external thermal network containing similar structure. Under appropriate parameter constellation we have two voltage sources nearly parallel only separated by their series resistors.
DEVpred() of charge node needs state vector update before
The answer is outstanding: Yes, we have to omit integration for the selfheating CTH current of the diode in case of dc sweep after tran. My test files are attached. The results for dc sweep will be erroneous differ.
Your observations are reasonable. Even selfheating at DC is more or less useless except for debugging purpose we should correct this for all selfheating models (diode, vdmos and vbic). I will make few check's and come back here.
Made checks with your latest commits and bjt, diode and vbic. Everything OK. Also checked Verilog-A cmc_diode. The openvaf compiler prevents integration in dc range. So we have not the problem.
It is an ngspice bug - nothing to do with IHP PDK. Separate simulations are correct, dc before tran too. The case tran before has wrong dc results. Not only bjt's are affected, diodes too.
