Hello all, I have some kind of confusion about the min and max W,L for the devices in the pdk, for example, let’s say the standard 1.8V pfet, when i looked at its min and max W,L from its spice model file, it has min L of 0.145um and max L of 0.155um and min W of 1.255um and max W of 1.265um so an average L of 0.15um and an average W of 1.26um, whilst when i pick it up to use in xschem, it comes with a default L=0.15um and W=1um so that W value defies it min and max rule from its spice model but the simulation runs with no problem I don’t know how. Also when i took a look at the device details from the skywater website, i found out that they listed a table of parameters at different W/L‘s and these W/L values also defy their min and max from the spice model, as you can see from the picture I attached with this message. So please if anyone could settle this confusion for me, I’d be really grateful and thanks.

You are probably looking at some _rf models. Xschem does not have symbols for _rf models, however you can use rf models in simulation by placing a nfet_01v8 transistor and changing the model attribute. If you do so set L and W to the right values. _rf transistros have a fixed layout so only one W and one L are allowed for a given model. There are numerous different _rf models to cover a reasonable discrete W/L space.

@Stefan Schippers no actually i was looking at the standard pfet 01v8 spice model file not the rf spice model file, i know that the rf devices have only one W and one L but after looking through the file of the standard pfet 01v8, i found out that it has many lines of min and max W,L , do you have any idea what does that mean ?

@mohamed hassan find this file in the pdk:

sky130_fd_pr__pfet_01v8__tt.pm3.spice

, then do this operation:

grep lmin  sky130_fd_pr__pfet_01v8__tt.pm3.spice

you get the allowed ranges:

schippes@asus:~/share/pdk/sky130A/libs.ref/sky130_fd_pr/spice$ grep lmin  sky130_fd_pr__pfet_01v8__tt.pm3.spice
+ lmin = 2.0e-05 lmax = 1.0e-04 wmin = 7e-06 wmax = 1.0e-4
+ lmin = 8e-06 lmax = 2.0e-05 wmin = 7e-06 wmax = 1.0e-4
+ lmin = 4e-06 lmax = 8e-06 wmin = 7e-06 wmax = 1.0e-4
+ lmin = 2e-06 lmax = 4e-06 wmin = 7e-06 wmax = 1.0e-4
+ lmin = 1e-06 lmax = 2e-06 wmin = 7e-06 wmax = 1.0e-4
+ lmin = 5e-07 lmax = 1e-06 wmin = 7e-06 wmax = 1.0e-4
+ lmin = 2.5e-07 lmax = 5e-07 wmin = 7e-06 wmax = 1.0e-4
+ lmin = 1.8e-07 lmax = 2.5e-07 wmin = 7e-06 wmax = 1.0e-4
+ lmin = 1.5e-07 lmax = 1.8e-07 wmin = 7e-06 wmax = 1.0e-4
+ lmin = 2.0e-05 lmax = 1.0e-04 wmin = 5.0e-06 wmax = 7.0e-6
+ lmin = 8e-06 lmax = 2.0e-05 wmin = 5.0e-06 wmax = 7.0e-6
+ lmin = 4e-06 lmax = 8e-06 wmin = 5.0e-06 wmax = 7.0e-6
+ lmin = 2e-06 lmax = 4e-06 wmin = 5.0e-06 wmax = 7.0e-6
+ lmin = 1e-06 lmax = 2e-06 wmin = 5.0e-06 wmax = 7.0e-6
+ lmin = 5e-07 lmax = 1e-06 wmin = 5.0e-06 wmax = 7.0e-6
+ lmin = 2.5e-07 lmax = 5e-07 wmin = 5.0e-06 wmax = 7.0e-6
+ lmin = 1.8e-07 lmax = 2.5e-07 wmin = 5.0e-06 wmax = 7.0e-6
+ lmin = 1.5e-07 lmax = 1.8e-07 wmin = 5.0e-06 wmax = 7.0e-6
+ lmin = 2.0e-05 lmax = 1.0e-04 wmin = 3.0e-06 wmax = 5.0e-6
+ lmin = 8e-06 lmax = 2.0e-05 wmin = 3.0e-06 wmax = 5.0e-6
+ lmin = 4e-06 lmax = 8e-06 wmin = 3.0e-06 wmax = 5.0e-6
+ lmin = 2e-06 lmax = 4e-06 wmin = 3.0e-06 wmax = 5.0e-6
+ lmin = 1e-06 lmax = 2e-06 wmin = 3.0e-06 wmax = 5.0e-6
+ lmin = 5e-07 lmax = 1e-06 wmin = 3.0e-06 wmax = 5.0e-6
+ lmin = 2.5e-07 lmax = 5e-07 wmin = 3.0e-06 wmax = 5.0e-6
+ lmin = 1.8e-07 lmax = 2.5e-07 wmin = 3.0e-06 wmax = 5.0e-6
+ lmin = 1.5e-07 lmax = 1.8e-07 wmin = 3.0e-06 wmax = 5.0e-6
+ lmin = 2.0e-05 lmax = 1.0e-04 wmin = 2e-06 wmax = 3.0e-6
+ lmin = 8e-06 lmax = 2.0e-05 wmin = 2e-06 wmax = 3.0e-6
+ lmin = 4e-06 lmax = 8e-06 wmin = 2e-06 wmax = 3.0e-6
+ lmin = 2e-06 lmax = 4e-06 wmin = 2e-06 wmax = 3.0e-6
+ lmin = 1e-06 lmax = 2e-06 wmin = 2e-06 wmax = 3.0e-6
+ lmin = 5e-07 lmax = 1e-06 wmin = 2e-06 wmax = 3.0e-6
+ lmin = 2.5e-07 lmax = 5e-07 wmin = 2e-06 wmax = 3.0e-6
+ lmin = 1.8e-07 lmax = 2.5e-07 wmin = 2e-06 wmax = 3.0e-6
+ lmin = 1.5e-07 lmax = 1.8e-07 wmin = 2e-06 wmax = 3.0e-6
+ lmin = 2.0e-05 lmax = 1.0e-04 wmin = 1.68e-06 wmax = 2.0e-6
+ lmin = 8e-06 lmax = 2.0e-05 wmin = 1.68e-06 wmax = 2.0e-6
+ lmin = 4e-06 lmax = 8e-06 wmin = 1.68e-06 wmax = 2.0e-6
+ lmin = 2e-06 lmax = 4e-06 wmin = 1.68e-06 wmax = 2.0e-6
+ lmin = 1e-06 lmax = 2e-06 wmin = 1.68e-06 wmax = 2.0e-6
+ lmin = 5e-07 lmax = 1e-06 wmin = 1.68e-06 wmax = 2.0e-6
+ lmin = 2.5e-07 lmax = 5e-07 wmin = 1.68e-06 wmax = 2.0e-6
+ lmin = 1.8e-07 lmax = 2.5e-07 wmin = 1.68e-06 wmax = 2.0e-6
+ lmin = 1.5e-07 lmax = 1.8e-07 wmin = 1.68e-06 wmax = 2.0e-6
+ lmin = 2.0e-05 lmax = 1.0e-04 wmin = 1.65e-06 wmax = 1.68e-6
+ lmin = 8e-06 lmax = 2.0e-05 wmin = 1.65e-06 wmax = 1.68e-6
+ lmin = 4e-06 lmax = 8e-06 wmin = 1.65e-06 wmax = 1.68e-6
+ lmin = 2e-06 lmax = 4e-06 wmin = 1.65e-06 wmax = 1.68e-6
+ lmin = 1e-06 lmax = 2e-06 wmin = 1.65e-06 wmax = 1.68e-6
+ lmin = 5e-07 lmax = 1e-06 wmin = 1.65e-06 wmax = 1.68e-6
+ lmin = 2.5e-07 lmax = 5e-07 wmin = 1.65e-06 wmax = 1.68e-6
+ lmin = 1.8e-07 lmax = 2.5e-07 wmin = 1.65e-06 wmax = 1.68e-6
+ lmin = 1.5e-07 lmax = 1.8e-07 wmin = 1.65e-06 wmax = 1.68e-6
+ lmin = 2.0e-05 lmax = 1.0e-04 wmin = 1.26e-06 wmax = 1.65e-6
+ lmin = 8e-06 lmax = 2.0e-05 wmin = 1.26e-06 wmax = 1.65e-6
+ lmin = 4e-06 lmax = 8e-06 wmin = 1.26e-06 wmax = 1.65e-6
+ lmin = 2e-06 lmax = 4e-06 wmin = 1.26e-06 wmax = 1.65e-6
+ lmin = 1e-06 lmax = 2e-06 wmin = 1.26e-06 wmax = 1.65e-6
+ lmin = 5e-07 lmax = 1e-06 wmin = 1.26e-06 wmax = 1.65e-6
+ lmin = 2.5e-07 lmax = 5e-07 wmin = 1.26e-06 wmax = 1.65e-6
+ lmin = 1.8e-07 lmax = 2.5e-07 wmin = 1.26e-06 wmax = 1.65e-6
+ lmin = 1.5e-07 lmax = 1.8e-07 wmin = 1.26e-06 wmax = 1.65e-6
+ lmin = 2.0e-05 lmax = 1.0e-04 wmin = 1e-06 wmax = 1.26e-6
+ lmin = 8e-06 lmax = 2.0e-05 wmin = 1e-06 wmax = 1.26e-6
+ lmin = 4e-06 lmax = 8e-06 wmin = 1e-06 wmax = 1.26e-6
+ lmin = 2e-06 lmax = 4e-06 wmin = 1e-06 wmax = 1.26e-6
+ lmin = 1e-06 lmax = 2e-06 wmin = 1e-06 wmax = 1.26e-6
+ lmin = 5e-07 lmax = 1e-06 wmin = 1e-06 wmax = 1.26e-6
+ lmin = 2.5e-07 lmax = 5e-07 wmin = 1e-06 wmax = 1.26e-6
+ lmin = 1.8e-07 lmax = 2.5e-07 wmin = 1e-06 wmax = 1.26e-6
+ lmin = 1.5e-07 lmax = 1.8e-07 wmin = 1e-06 wmax = 1.26e-6
+ lmin = 2.0e-05 lmax = 1.0e-04 wmin = 8.4e-07 wmax = 1.0e-6
+ lmin = 8e-06 lmax = 2.0e-05 wmin = 8.4e-07 wmax = 1.0e-6
+ lmin = 4e-06 lmax = 8e-06 wmin = 8.4e-07 wmax = 1.0e-6
+ lmin = 2e-06 lmax = 4e-06 wmin = 8.4e-07 wmax = 1.0e-6
+ lmin = 1e-06 lmax = 2e-06 wmin = 8.4e-07 wmax = 1.0e-6
+ lmin = 5e-07 lmax = 1e-06 wmin = 8.4e-07 wmax = 1.0e-6
+ lmin = 2.5e-07 lmax = 5e-07 wmin = 8.4e-07 wmax = 1.0e-6
+ lmin = 1.8e-07 lmax = 2.5e-07 wmin = 8.4e-07 wmax = 1.0e-6
+ lmin = 1.5e-07 lmax = 1.8e-07 wmin = 8.4e-07 wmax = 1.0e-6
+ lmin = 2.0e-05 lmax = 1.0e-04 wmin = 6.4e-07 wmax = 8.4e-7
+ lmin = 8e-06 lmax = 2.0e-05 wmin = 6.4e-07 wmax = 8.4e-7
+ lmin = 4e-06 lmax = 8e-06 wmin = 6.4e-07 wmax = 8.4e-7
+ lmin = 2e-06 lmax = 4e-06 wmin = 6.4e-07 wmax = 8.4e-7
+ lmin = 1e-06 lmax = 2e-06 wmin = 6.4e-07 wmax = 8.4e-7
+ lmin = 5e-07 lmax = 1e-06 wmin = 6.4e-07 wmax = 8.4e-7
+ lmin = 2.5e-07 lmax = 5e-07 wmin = 6.4e-07 wmax = 8.4e-7
+ lmin = 1.8e-07 lmax = 2.5e-07 wmin = 6.4e-07 wmax = 8.4e-7
+ lmin = 1.5e-07 lmax = 1.8e-07 wmin = 6.4e-07 wmax = 8.4e-7
+ lmin = 2.0e-05 lmax = 1.0e-04 wmin = 5.5e-07 wmax = 6.4e-7
+ lmin = 8e-06 lmax = 2.0e-05 wmin = 5.5e-07 wmax = 6.4e-7
+ lmin = 4e-06 lmax = 8e-06 wmin = 5.5e-07 wmax = 6.4e-7
+ lmin = 2e-06 lmax = 4e-06 wmin = 5.5e-07 wmax = 6.4e-7
+ lmin = 1e-06 lmax = 2e-06 wmin = 5.5e-07 wmax = 6.4e-7
+ lmin = 5e-07 lmax = 1e-06 wmin = 5.5e-07 wmax = 6.4e-7
+ lmin = 2.5e-07 lmax = 5e-07 wmin = 5.5e-07 wmax = 6.4e-7
+ lmin = 1.8e-07 lmax = 2.5e-07 wmin = 5.5e-07 wmax = 6.4e-7
+ lmin = 1.5e-07 lmax = 1.8e-07 wmin = 5.5e-07 wmax = 6.4e-7
+ lmin = 2.0e-05 lmax = 1.0e-04 wmin = 4.2e-07 wmax = 5.5e-7
+ lmin = 8e-06 lmax = 2.0e-05 wmin = 4.2e-07 wmax = 5.5e-7
+ lmin = 4e-06 lmax = 8e-06 wmin = 4.2e-07 wmax = 5.5e-7
+ lmin = 2e-06 lmax = 4e-06 wmin = 4.2e-07 wmax = 5.5e-7
+ lmin = 1e-06 lmax = 2e-06 wmin = 4.2e-07 wmax = 5.5e-7
+ lmin = 5e-07 lmax = 1e-06 wmin = 4.2e-07 wmax = 5.5e-7
+ lmin = 2.5e-07 lmax = 5e-07 wmin = 4.2e-07 wmax = 5.5e-7
+ lmin = 1.8e-07 lmax = 2.5e-07 wmin = 4.2e-07 wmax = 5.5e-7
+ lmin = 1.5e-07 lmax = 1.8e-07 wmin = 4.2e-07 wmax = 5.5e-7

@Stefan Schippers perfect, thanks a lot Mr stefan Would you mind if i message you privately to ask you a couple of questions regarding the pdk since I’m very new to it and I’m currently using it in my graduation project?

ok no problem