View source for SKY130 Models

== Step 1: == 
Installing the [https://www.skywatertechnology.com/ SkyWater] SKY130 130nm CMOS models from the Github repository requires [https://git-scm.com/downloads installing git]. You can also just got to the [https://github.com/google/skywater-pdk-libs-sky130_fd_pr SkyWater github page] and just download the files as one zip file.

== Step 2: ==
After installing git, you can clone the SKY130 libraries into a directory, e.g. <code>/home/louis/git/sky130</code> in your filesystem, assuming <code>/home/louis/git</code> (or your equivalent home directory) already exists, by:

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<source lang="bash">
cd ~/git
mkdir ./sky130
cd ./sky130
git clone https://github.com/google/skywater-pdk-libs-sky130_fd_pr.git
</source>
</div>

Note that if you downloaded the zip file instead, you should get the same directory structure by uncompressing the zip file into your local directory (e.g. <code>/home/louis/git/sky130</code>).

== Step 3: ==
To instantiate SKY130 devices into your SPICE deck, add the following commands to access the typical (tt) model corner:

<div style="margin-left: 2em;">
<source lang="bash">
* Include SkyWater sky130 device models
.lib "/home/louis/git/sky130/skywater-pdk-libs-sky130_fd_pr/models/sky130.lib.spice" tt
.option scale=1e-6
</source>
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Since these are relatively complex, the models are not native transistors, but subcircuits. So to instantiate a low threshold voltage (LVT) 1.8V NMOS transistor with a width of 1&mu;m and a length of 0.5&mu;m, you will need to use the 'x' device prefix instead of the 'm' prefix:

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<source lang="bash">
xm1	d1 g1 0 0	sky130_fd_pr__nfet_01v8_lvt w=1 l=0.5
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Thus, a complete SPICE deck for obtaining the transfer and output characteristics of the 1.8V LVT NMOS would look like:

<div style="margin-left: 2em;">
<source lang="bash">
* NMOS Transfer and Output Characteristics
* Generated 10-Oct-2021 10:31:26
.option scale=1e-6 abstol=1e-18 vntol=1e-12
* Include SkyWater sky130 device models
.lib "/home/louis/git/sky130/skywater-pdk-libs-sky130_fd_pr/models/sky130.lib.sp
ice" tt
xm1	d1 g1 0 0	sky130_fd_pr__nfet_01v8_lvt w=1 l=0.5
vgs	g1 0		dc=0.9
vds	d1 0		dc=0.9
.control
dc vgs 0 1.8 0.01
wrdata nmos_01v8_transfer_tt.dat -i(vds)
dc vds 0 1.8 0.01
wrdata nmos_01v8_output_tt.dat -i(vds)
.endc
.end
</source>
</div>