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 symbols for two inverters having sizes of: 
• 12u/6u (= width of the PMOS / width of the NMOS with both devices having minimum lengths of 0.6u)
• 48u/24u where the devices use a multiplier, M = 4 (set along with the width and length of the MOSFET, image), as seen below 

• Example layouts 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 ntap cell 
• Ground (gnd!) is connected to the p-substrate using the ptap cell
• Running power and ground with a single row of contacts, instead of 2 as seen below, is fine to reduce layout size
• Your schematics should have two pins, e.g., A and Ai
• Your layouts should have 4 pins: A, Ai, vdd!, and gnd! (note how lowercase letters are used for power and ground)
• Your lab reports should document your efforts and results including showing that the extracted layouts and schematics LVS correctly
• Zip up these cells in a directory call lab5_rjb.zip (last two or three letters are your initials) and link to your lab report
  

• Using SPICE simulate the operation of both of your inverters showing each driving a 100 fF, 1 pF, 10 pF, and 100 pF capacitive load
• Comment, in your report, on the results

• Use UltraSim (Cadence's fast SPICE simulator for larger circuits at the cost of accuracy) and repeat the above simulations 
• Use Setup -> Simulator/Directory/Host and select UltraSim as seen below
• You'll also have to point to the MOSFET models again as seen below
• Note that UltraSim only performs transient simulations (not AC, Noise, DC, operating point, etc.)  
• Not knowing this last item will lead to wasted time if trying to use UltraSim exclusively for simulations  

• The cells used to generate the images used on this webpage are found in lab5.zip

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).