Gordon W. Roberts
McGill University
Title:
"Test Methods For Sigma-Delta Data Converters And Related Devices"
Abstract:
This tutorial will look at the fundamental methods of digital sampling and
how to apply it to sigma-delta modulators and other sigma-delta based
devices. We begin by describing the principles of digital sampling and how
one extends this theory to the test of sigma-delta based data converters
and related devices. A review of the basic ideas of coherent testing will
be given, such as the application of the M/N coherency principle for
performing gain, frequency and distortion type
measurements. The impact of clock jitter will also be emphasized. Next,
we'll extend the sampling principle to the non-coherent test situation and
describe how one performs measurements of deterministic and random signals
using a pre-processing step involving windowing. Subsequently, the concept
of a periodogram will be introduced and shown how it is used to estimate
the power spectral density of a random signal (i.e., noise). At this point
in the discussion we'll review the basic ideas behind sigma-delta
modulators and their application to data conversion. We'll look at lowpass
and bandpass type modulators, as well as single-loop, multi-loop
multi-stage, continuous-time and sampled-data
implementations. The goal is to expose the students to the underlying
principles behind new IC developments and trends, rather than expose the
students to detail design issues. At this point, specific issues related
to estimating the power spectral density of a sigma-delta modulator using
a periodogram will be described. The remainder of the tutorial
will look at different ways in which sigma-delta techniques can be used
for Design-For-Test. One section will describe different methods in which
to generate high-precision analog signals, such as DC, sinusoids,
multi-tones, Gaussian noise signals, phase and frequency modulated
signals, etc. Such methods have application for retrofitting digital
testers as mixed-signal testers, as well as extending the capability of
existing testers. Subsequently, we'll demonstrate how sigma-delta
methods can be used in a wide range of DFT/BIST circuits for SOC
applications. This will include signal sources, digitizers, coherent
samplers, time-domain reflectometry and transmission, and noise and jitter
analyzers.
Biography:
Gordon W. Roberts received the B.A.Sc. degree from the University of
Waterloo, Canada, in 1983 and the M.A.Sc. and PhD degrees from the
University of Toronto, Canada, in 1986 and 1989, respectively, all in
electrical engineering. Dr. Roberts is currently a full professor at
McGill University where he holds the James McGill Chair in Electrical and
Computer Engineering. Over the years, he has conducted extensive research
on analog integrated circuit design and mixed-signal test issues. He has
co-written two undergraduate textbooks, entitled: SPICE For
Microelectronic Circuits with Prof. Adel Sedra and An Introduction to
Mixed-Signal IC Test Measurement with Mark Burns. He also co-written three
research monographs, Analog Test Signal Generation Using Periodic
SD-Encoded Data Streams (with Benoit Dufort), Analog Signal Generation For
Built-In Self-Test Of Mixed-Signal Integrated Circuits (with Albert Lu),
and Design and Analysis of Log-Domain Filter Circuits (with Vincent
Leung). He has published over 110 papers in scientific journals and
conferences, and he has contributed 11 chapters to other books. He is past
associate editor of the IEEE Transaction on Circuits and Systems, Part II,
and past associate editor for the IEEE Design & Test of
Computers Magazine. Prof. Roberts was also a past Distinguished Lecturer
for the IEEE Computer Society and the Circuits and Systems Society.. Prof.
Roberts has received numerous department, faculty and university awards
for teaching test and electronics to undergraduates, and received several
IEEE awards for his work on mixed-signal testing. Prof. Roberts is
presently the program chair of the IEEE International Test Conference. Dr.
Roberts is a Fellow of the IEEE. In 2003 he took leave from McGill to help
start DFT Microsystems, Inc, a company specializing in
high-speed timing measurement. His current research includes analog IC
design methods and various issues related to mixed-signal test.
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