Its been quite a while since my last post, but not with out reason. I’ve been plenty busy between school, work, and trying to be at least a little social all the while. I have a couple topics in the works, so here’s the first.
I’m currently taking an analog circuit design class. More specifically, monolithic circuit design – that is, IC circuits. For our first of two projects, we were to design a video repeater with a switchable output impedance for interfacing with different types of cables. The design specs were:
-Voltage Gain (loaded) = 2.5
-Bandwidth = 300MHz
-Input Impedance = 50 ohms
-Output Impedance = 50/75 ohms (switchable)
All the above specs were to stay within +/- 20% of the nominal value over process variation (inaccuracies in transistor manufacturing), supply voltage variation (1.08-1.32V), and temperature variation (25-85 deg. Celsius). My design maintains +/-10% for most specs, the only exception being the input impedance, maintaining +20/-5%.
Being that we can’t exactly afford to fabricate the ICs, we didn’t get quite that far. However, we did everything up to that point from conceptual design to initial SPICE simulation to physical layout. We finished up by extracting the parasitics from our layout and doing final simulations of a fabricated IC.
Here’s the paper I wrote summarizing my design strategy and results. It was limited to 4 pages, so its a bit hand-wavy in places, but the basic ideas are there.
