nmos_pmos_BSIMBULK.sp failed

[laurentc2]

Hi,

I have recompiled all the models in Ngspice_OpenVAF_Enhancements/VA_TEST/VA-Models-main/code with Ngspice_OpenVAF_Enhancements/bin/linux/intel/openvaf-r
I have tried on linux/intel to simulate with Ngspice_OpenVAF_Enhancements/bin/linux/intel/ngspice binary
to simulate the file Ngspice_OpenVAF_Enhancements/ngspice-46/examples/osdi/bsimbulk/netlist_mod_pmos.sp
but I got a lot of errors :

Using SPARSE 1.3 as Direct Linear Solver
Warning: singular matrix:  check node np1#t

Note: Starting dynamic gmin stepping
Warning: singular matrix:  check node np1#t

Warning: singular matrix:  check node np1#t

Warning: singular matrix:  check node np1#t

Warning: singular matrix:  check node np1#t

Warning: singular matrix:  check node np1#t

Warning: Dynamic gmin stepping failed
Note: Starting true gmin stepping
Warning: True gmin stepping failed
Note: Starting source stepping
Warning: source stepping failed
Note: Transient op started
Error: Transient op failed, timestep too small


Error: The operating point could not be simulated successfully.
	Any of the following steps may fail.!

doAnalyses: DC:  Timestep too small;  vgsn = 0:  vbsn = 0: cause unrecorded.


dc simulation(s) aborted
Error: no such vector vssn#branch

Error: no such vector vssn#branch
  in term: abs(vssn#branch)

I works very well with the latest regular ngspice 47, so do you know what I missed with your version ?

Laurent

[javaNoviceProgrammer]

The main reason is that ngspice silently drops unconnected and omitted osdi device terminals. The Verilog-A model has a thermal node (last terminal denoted by 't') and it is dropped in the netlist. The reason I changed this behavior was the $port_connected() function specification in Verilog-A. My ngspice binary will warn you about devices in the netlist whose number of terminals don't match the Verilog-A terminals.
The solution is to explicitly add thermal terminals of the transistors in the netlist.

[javaNoviceProgrammer]

@laurentc2 : please carefully read the following enhancement doc:

https://github.com/javaNoviceProgrammer/Ngspice_OpenVAF_Enhancements/blob/main/enhancements_doc/Enhancement-402.md

[laurentc2]

Hi Meisam,

It indeed works if I add T1 and T2, but then the netlist has to be patched after Kicad or xschem generation ... so bad for the EDA flow, and the designers don't like to patch their netlist because of the risk of a bad patch.
As it works for the regular ngspice-47, it would be nice if you can find a trick to make it works as for your ngspice + openvaf-r 😉

By the way, I also found a problem with the netlist : Ngspice_OpenVAF_Enhancements/ngspice-46/examples/osdi/r2_cmc/res_r2_cmc.cir

BRgds,
Laurent