The final project for Cooper Union course EE143 - Integrated Circuit Engineering, taught by Professor Toby Cumberbatch in Spring 2000 was a 3-Bit Flash Analog to Digital Converter. The converter was required to produce accurate output under variable temperature and rail voltage conditions. Thus a voltage reference was designed for minimal temperature and rail voltage dependance, and then divided with a polysilicon resistive network to produce the various reference voltages required by comparator circuits in the A/D converter. The image below shows a complete layout for a 3-bit Flash A/D converter, including the voltage reference circuit, 7 comparators in a "thermometer" configuration, and the necessary logic to produce a binary coded output from the thermometer code produced by the comparators.The circuit takes one input (an analog voltage signal) and produces 3 output bits at CMOS logic levels. The layout was produced using Virtuoso (part of the Cadence integrated circuit design software suite), and the image below is a screenshot.The circuit was designed by myself (Shabsi Walfish) and my partner Omar Badoolah. Please note that it may take some time to load on slower connections.

Below is an image of the full chip layout, including six analog to digital converter circuits and two operational amplifiers (not to mention signatures for me and my partner). The circuit is presently in the production queue at MOSIS, awaiting fabrication.



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