EE 421L Digital Integrated Circuit Design - Lab 5

Design, layout, and simulation of a CMOS inverter

Pre-lab work

• Back-up all of your work from the lab and the course.
• Go through Tutorial 3 seen here.

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• Draft schematics, layouts, and icons for inverters having drawn sizes of: 
• 20/10 (= width of the PMOS / width of the NMOS with both devices having minimum lengths of 2)
• 100/50 where the PMOS is 20/2 with M = 5 (5 MOSFETs in parallel to get 80 and 40, set multiplier as seen below)

• Examples are seen below.
• Notice that power is run on the top of the cell via metal1 and ground is run on the bottom of the cell also via metal1
• Power (vdd) is connected to the n-well using the Metal-1-N-Well-Con node
• Ground (gnd) is connected to the p-substrate using the Metal-1-P-Well-Con node
• Running power and ground with a single row of contacts, instead of 3 as seen below, is fine to reduce layout size
• Your schematics should have two exports, e.g., In and Out
• Your layouts should have 4 exports: In, Out, vdd, and gnd (note how lowercase letters are used for power and ground)
• Your lab reports should document your efforts and results

• Using SPICE simulate the operation of your inverters showing each driving a 100 fF, 1 pF, and 10 pF capacitors
• Comment, in your report, on the results
• Use ALS (Tools -> Simulation (Built-in)) to simulate the operation of your inverters driving these capacitive loads (see Electric_video_12 here)
• Ensure your lab report provides discussion on using ALS (providing inputs, plotting, limitations [does the delay change with load? Why or why not?], etc.)
• Repeat these simulations using IRSIM (link, see 12.) 
• Note that while ALS is a logic simulator, and thus of limited use for transistor-level design, IRSIM does model transistors (so we can simulate delays) so it's very useful for digital design
• To zoom in, out, and fit in the waveform viewer use the same menu commands used with layout, schematic, and icon views
• As always don't use special characters, e.g. # $ % ^ -, in signal names. IRSIM doesn't operate correctly when these characters are used

As always ensure that your html lab report includes your name and email address at the beginning of the report (the top of the webpage).
When finished backup your work (webpages and design directory).