SKY130 Basics - Using Xschem

[@NithinPurushothama]

Bro how can i plot various mosfet parameters like gm, cgs for better understanding like we do in cadence

[@zinhaboussi]

Thank you for making tutorials about open source eda

[@matthewlumb8478]

Thanks very much - a really useful video that helped to get me started with Xschem. One question though, when you display all the attributes of the nfet after the first simulation, the dimensions show 5 fingers and a width of 2 microns - different to the schematic (I was comparing my gm and Vt outputs to yours and noticed the difference). Do you have another nfet on the schematic we can't see?

[@ryanwans391]

Ah yes! I didn’t catch this at first. I had originally set up a different test structure to the side, which is why my values did not change after a second simulation and the sizing looks off

[@adithyaav9153]

Why do we only get one gm, gds, ...etc ? Shouldn't these parameters vary with Vgs ?

[@ryanwans391]

It gives you parameter values of gm, gds, etc. of the last voltage in the sweep. In this case Vgs was swept up to 3V, so the gm and gds are representative of Vgs = 3.0 V

[@whysathwik]

hey how do i check where my .lib.spice is?? please help

[@FengruiZuo]

the gm seems so exceedingly small, using the lvt transistor I was able to get around 0.4mS. e-12 doesn't make sense..

[@ryanwans391]

Yeah I noticed that too originally. I think I ended up updating Ngspice and got more accurate results

[@HansBaier]

Great tutorial, thanks 👍🏻👍🏻👍🏻

[@OKRunning]

Hi, could you make a how to install xschem with all needed tools? I'm on my third try :(

[@ryanwans391]

Sure! It’s definitely a tedious process. What I’m using in this video is the sky130 docker container, it bundles everything into a container and is very easy to install. github.com/efabless/foss-asic-tools

[@joanrivi8692]

Thanks

[@DonaldHernandez-d8m]

Edwardo Path

[@lowellbowers8328]

🙌 𝕡𝕣𝕠𝕞𝕠𝕤𝕞