Hi guys, I just started using sky130pdk. Here, the models given in examples are labelled as FET dev...

srinivasan_muthukrishnan19

01/09/2023, 10:02 AM

Hi guys, I just started using sky130pdk. Here, the models given in examples are labelled as FET device. Is there normal device available or only FET's are available?

✅ 1

Stefan Schippers

01/09/2023, 10:58 AM

Xschem comes with a `devices`/ library containing all ideal spice components like capacitor, resistor, inductr, voltage source, current source, controlled current/voltage sources and so on. This library includes also specific xschem symbols for input/output pins, net labels, code blocks. The

sky130_fd_pr/

directory contains all sky130 silicon devices, these are mosfets, silicon/poly resistor, mos varactors, Metal Insulator Metal (MIM) capacitors, bipolar transistors, diodes, ...

srinivasan_muthukrishnan19

01/09/2023, 11:28 AM

my doubt was is

sky130_fd_pr/

does have mosfets or is it only FINFETS? regarding corner files , in

sky130_fd_pr/corner.sym

Only corner tt is available, can we directly change or should we have model file for PVT variation for slow, fast and other cases? I attach the image for reference.

Stefan Schippers

01/09/2023, 11:54 AM

The various

nfet_*

and

pfet_*

models are MOS transistors, there are no FinFets. for the corner you can set

corner=tt, corner=ff, corner=ss, forner=fs, corner=sf

. the

*_mm

variants (

tt_mm, ss_mm, ff_mm, fs_mm ....

) are for mismatch/montecarlo simulations. Don't use these unless you are running multiple simulations to see the effect of variations in your circuit.

srinivasan_muthukrishnan19

01/09/2023, 11:57 AM

ok thanks for the heads up.

srinivasan_muthukrishnan19

01/09/2023, 1:16 PM

@Stefan Schippers for saving plots, should we learn how to write code_shown.sym in spice format?

Stefan Schippers

01/09/2023, 2:00 PM

Yes, xschem comes with numerous examples, you can look into these as well as learn the ngspice user manual.

Stefan Schippers

01/09/2023, 2:03 PM

the commands for saving the simulation results to a file are usually something like:

Copy code

.option savecurrents
.control
  save all
  tran  // ac //  dc // whatever simulation command
  write circuit_name.raw
.endc

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