Can we only vary W of MOSFET models in xschem? Are there any other parameters we can control?

@Binoy B you can vary

W

,

L

,

ad

,

as

,

pd

,

ps

,

nrd

,

nrs

,

sa

,

sb

,

sd

,

nf

and

mult

. You can also change the model, although this is bad practice, if you need a different transistor pick the right symbol. In most cases you only change W and L, xschem computes the other parameters to get a reasonable default, however you can set your own values .

@Stefan Schippers what are w, l, as, pd, ps, nrd, nrs, sa, sb ad, nd and mult. Where can I find the definitions of those?

Look in the ngspice user manual, chapter 11.1

mult

is the multiplication factor, so setting mult=4 means 4 identical parallel devices.

nf

is the number of fingers. Given the total width W=2, for example, setting nf=2 means that the transistor is drawn with 2 gate fingers with W=1

@Stefan Schippers how to include the reram spice model you have shared in skywater pdk?

for model parametrs (sky130 uses bsim4) see this list. For reram you must look to @Barak Hoffer repository and/or ask @Talha Bin Azmat https://github.com/barakhoffer/sky130_xyce_reram

@Binoy B You have to use the xyce simulator for that. The .va will be converted into a format that is readable by xyce. So first you will need to convert that using xyce builttoolplugin. Check out the discussions in reram channel. You can learn about it there. And you wont be using ngspice. For some reason ngspice can simulate reram.va model. So you should look around on how to use xyce with xschem. And then use xyce to simulate all your circuits that contain reram module

@Talha Bin Azmat Thank you for support. I have yet to test myself the reram, i have a list of things to do so haven't had time to that, and for that reason i can not support others directly.

@Talha Bin Azmat so xschem cant be used for reram simulation? There is xyce support in xschem, right?

@Binoy B xschem is a schematic editor, if you place a reram in a schematic what xschem does is generating a netlist that contains one line (or more) for the reram device with its connections to the other nodes. Xschem supports xyce. In order for xyce to simulate the reram you need to compile a verilogA model and let Xyce find and understand this model.