IEEE Solid-States Circuits Magazine - Spring 2020 - 86

In Memory of Rudy van de Plassche (1941-2019)

I

I met Rudy van de Plassche for the
first time in 1988, at a coffee machine
on the fifth floor of a building on the
campus of Philips Research Labo-
ratories in Eindhoven, The Nether-
lands. At that time, I did not know
who he was. He was just a friendly
man talking to me when I started my
first real job. That was Rudy, a hum-
ble, down-to-earth, and nice man.
Of course, my colleagues would
soon tell me that this was Rudy van
de Plassche, a world-famous analog
designer, particularly in the field of
analog-to-digital converters (ADCs).
At that time, Rudy already had more
patents to his name (then close to 50
and currently 76) than anybody else
at Philips Research, which was huge,
with more than 4,000 employees
worldwide and more than 3,000 just
at the site in The Netherlands.
Rudy was the inventor of many
circuits and circuit ideas that have
become commonplace. To mention a
few, he invented folding (1979) and
interpolating (1988) ADCs, capaci-
tive feedforward compensation for
transconductance amplifiers (1971),
an auto-zeroed sample and hold cir-
cuit (1986), and chopper-stabilized
amplifiers and dynamic element
matching (1976).
As successful as Rudy was in his
career, he also encountered setbacks.
After he returned to Philips Research
in Eindhoven in 1986 following a
three-year stint at the company's
laboratories in Sunnyvale, California,
surprisingly enough, he was asked
to work on digital radio, a different
topic than his beloved data convert-
ers. Rudy thought about it and con-
cluded that the most critical building
block for a digital radio would be the
data converter. He needed someone to
work on the data converter, and, as it
turned out, that was my lucky break.

Digital Object Identifier 10.1109/MSSC.2020.2987239
Date of current version: 24 June 2020

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Rudy wanted to implement fold-
ing in CMOS, a technique that until
that point had been applied only in
bipolar technologies. As he could not
do it himself, he approached me and
asked me to investigate whether this
could be done in CMOS. At that point,
I had no experience in data convert-
ers. I looked at the idea for a while,
ran some simulations, and came to
the conclusion that this could very
well be done in CMOS. Triggered by
this finding, Rudy asked me whether
I could run some more simulations,
which of course I did. Working with
Rudy was terrific. To make a long
story short, in the end, he asked me to
finish the design and build a real ADC
based on it. I did, and it worked well.
This episode was the starting point
for my collaboration with Rudy.
I had moved on to work at Broad-
com (Irvine, California), a small
start-up company at that time. Not
much later, I learned that Rudy,
unhappy about not working on data
converters, made a career change
as well and became a full-time pro-
fessor at Eindhoven University. As I
was eager to work with Rudy again, I
called him to see if he could become
a consultant for Broadcom, so that
we could work together, and Rudy
agreed. His consultancy period in
Irvine was fantastic. Everyone in the
analog group loved working with
him, and there was so much to learn
from him.
In 1999, I started the Broadcom
design center in The Netherlands and
immediately asked Rudy to join us full
time. He quickly agreed and made the
entire analog team extremely happy
and me very proud as well. It was such
a joy for everyone to work with Rudy,
not only because of the immense
amount of knowledge he shared with
everyone but also because he was
always pleasant.
Rudy could get to the essence
of a circuit problem in just one or
two sentences. Of course, every now

IEEE SOLID-STATE CIRCUITS MAGAZINE	

and then he had to correct us in
our analysis of circuit problems. He
would always start that by saying,
"Well boss, ...", where he would use
the word "boss" in such a way that,
on the one hand, he made you feel
okay but, on the other hand, you'd
know that that word was the prelude
to a correction that you had better
listen to.
Everyone who knew Rudy will
agree that he was very modest, never
boasting about his successes. Even
his biographies hardly speak of his
achievements. Rudy authored more
than 50 publications and 76 patents.
For many years, he was part of the
International Solid-State Circuits
Conference (ISSCC) technical pro-
gram committee, chaired the ISSCC
European committee from 1995
to 2002, founded the Advances in
Analog Circuit Design (AACD) work-
shop together with Willy Sansen and
Johan Huijsing in 1980, was an IEEE
Fellow, received the Veder award of
the Dutch Stichting Wetenschappelijk
Radiofonds Veder, and was the first
European to receive the Solid-State
Circuits Award (now called the Don-
ald O. Pederson award).
With Rudy's passing, we lost not
only a giant in analog design, of
which there are only very few, but
also a very valued colleague and a
dear friend.
-Klaas Bult
✤✤✤
I learned about Rudy van de Plass-
che because of his first paper at
the ISSCC in 1971. It was what he
called a simple frequency compen-
sation technique for an operational
amplifier. I was pursuing my Ph.D.
degree at the University of Califor-
nia, Berkeley, at that time. Anything
presented at the ISSCC was top pri-
ority, which is why I feel so familiar
with his work.
That amplifier was obviously in
bipolar technology, an expertise
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