Vern05/07/2021, 11:51 AM
but I keep getting the following message:
alterparam XDUT.XMNDIO w=5.5 ... reset
That message suggests to me that ngspice was able to follow my path to the transistor subcircuit instance, but for whatever reason, it can't find the transistor's "w" parameter from there. Now, I checked to be sure and, yes, the FET subcircuit models do call the width parameter "w". Every parameter has the expected name, except, perhaps, for "M" being replaced with "mult". I mention the lower level of hierarchy because I found some threads from 2018 on ngspice's Sourceforge page about alterparam that seemed to suggest that, at least at the time, ngspice could not do
Error: parameter 'w' not found, command 'alterparam' skipped
on subcircuits below the top level. Anyone know if that is still true?
Tim Edwards05/07/2021, 1:08 PM
, I think, or something like that.
apparently operates on all parameters of all subcircuits, because
works, ignoring that it is a pretty useless command. What you want is
alterparam sky130_fd_pr__pfet_g5v0d10v5 w = 2
. However, I am having difficulty getting that to work with either
alter m.xc1.msky130_fd_pr__pfet_g5v0d10v5 w = 2
or `l`; ngspice keeps telling me
which indicates that it thinks there is no valid bin for that width and length, except that there is.
Error: no model available for w= 2.0 l = 0.8
Vern05/07/2021, 10:27 PM
commands. That would probably mean having to descend all the way down to the MOSFET instance inside the XM* subcircuit. I was really hoping to avoid having to dig down all the way to the MOSFET instance inside the subcircuit, what with the crazy long name it has and whatnot. Also, I seem to recall seeing there's more than one MOSFET instance inside the RF transistors. Probably be less trouble to just edit the DUT's schematic...