PJRC.COM Offline Archive, February 07, 2004
Visit this page on the live site

skip navigational linksPJRC
Shopping Cart Checkout Shipping Cost Download Website
Home MP3 Player 8051 Tools All Projects PJRC Store Site Map
You are here: Filter ASIC Main Page Search PJRC

Filter ASIC
selected Main Page
Project Spec
CMOS Layout

Fourth Order Low-Pass Filter ASIC

This IC, commonly refered to as "The Decimator", implements a fourth order (sinc4) digital low-pass filter. The intended application for this filter is to process output data from a multi-bit sigma-delta modulator, thus completing a high-resolution A/D converter system.

The entire design was completed in approximately 10 weeks in the Fall of 1993 by me (Paul Stoffregen), Shivani Gupta, and Srinivas Pattamatta as the project associated with the OSU-ECE graduate VLSI design course (ECE 517) instructed by Richard Schreier.

This full-custom CMOS layout was drawn using the CMOSN lambda-based design rules. The layout preview shown here is also available in medium, large, and huge sizes. After the course, the chip was fabricated by MOSIS using Orbit's 2um P-well process on a tiny-chip (2.2mm by 2.2mm) die.

chip All four chips fabricated by MOSIS were tested (at only moderate speed) using a microcontroller to feed data into the chip and collect the output. All four chips produced correct output results!

die photo

Content by Subject


Fourth Order Low-Pass Filter IC with Decimation Factor of 32 (aka "The Decimator")
Paul Stoffregen - Circuit Design, IC Layout, Spice Simulation
Shivani Gupta - Schematic Entry, Switch-Level Simulation
Srinivas Pattamatta (aka PVS) - Spice Simulation, Fiddling with CAD Software
Richard Schreier - Project Specification, Architecture Outline, Free Pizza
http://www.pjrc.com/tech/decm/index.html
Last updated: December 29, 2003
Suggestions, comments, criticisms?? Paul, Shivani, PVS, Richard