Featured Engineer

Interview with Bob Pease

Bob Pease

Bob Pease - Semi-retired after working for National Semiconductor for 34 years; Consultant, Hobbyist

  • Photos taken by Jason Doiy, Professional Photographer
How did you get into electronics/ engineering and when did you start?

I was 17 years old when I started. I built a Knight-kit 10-watt audio amplifier. When I was a kid I was not into car radios or things like that. I was not one of those kids who took apart my father’s car radio and put it back together and did it ten more times. I never did that. It is very simple. I came in late.

I was good at physics and math. In my senior year at MIT, I was taking some physics courses, I think it was course # 8.721 and I said, “This stuff isn’t physical anymore.” You know – - quantum theory and eigen vectors – - and then I thought maybe I should get into electronics, and I did, and it was fun! I had a good piece of luck; I think it was my sophomore year at MIT, with Len Kleinrock, who has recently been properly hailed, 50 years late, as one of the inventors of the internet. He was one of the better teachers I’ve had and I really enjoyed learning about electronics design.

Well, I am still doing design with Piecewise Linear Electronic Circuits and transistors. So that’s how I snuck up on electronics.

After MIT, where did you first go to work?

Even before I left MIT I went over to Philbrick Researches and I helped do some technical writing. I may not have been the best engineer at that time because I would have been as green as you can get, but I helped them produce some data sheets, which then got into more electronics and transistor design.

Before you got into designing IC’s, what were you doing?

I was doing board-level circuit design. And that was a lot of fun because we could make money out of it. One of my buddies invented the P2 which was about 3”x1.5”x1”. We were selling that thing that used about enough parts to make a seven-transistor AM radio, for $220. That was a lot of money back in 1961. So we figured out how to do things that other people were not able to do, we packaged them nicely, wrote good application notes and there you are. That was the Philbrick legacy.

You can still find the Philbrick Applications Manual here. Analog Devices was nice enough to publish it as a service to people who are trying to remember the “good old days” of engineering design.

Generally I do not do much digital. I know how to use a D-flip flop and gates, but I just do not do that much digital design. That is its own specialty. I have never made a mistake writing software because I do not write software.

Do you have any favorite circuits?

For many years one of my favorite circuits was the Philbrick 4701 voltage to frequency converter and it was .1% linear with a nice safety margin. It was revolutionary for its day. We would get out there and make several million dollars of revenue per year based on the voltage to frequency converter. The patent # is 3,746,968.

This circuit got patented, though the patent has long since expired, but it used a cheap LM301 and a few diodes to make a .1% linear converter. And if I went back in a time machine to 1940 I could build a 3 digit DVM to help the war effort, except for one thing: I could not solder and I was 1 year old. I would have had to show my mother how to solder and I did not know how to do that either.

Anyhow, some of these circuits are or have been revolutionary and some have been evolutionary. We keep having fun inventing circuits.

After working with George A. Philbrick Researches what did you do?

I worked there for 15 years, then I moved to Silicon Valley and have a lot of fun ever since! I worked for National Semiconductor for 34 years, starting in 1976.

Can you tell us a little more about your IC Design work?

I have designed about 27 linear ICs. I started at Philbrick and designed a few IC’s there. When I came to National they said “here is a linear data book and you have to be responsible for all the circuits for applications engineering,”and I said “Good, wonderful.” I learned everything I could about linear ICs and I started to work on the corners of projects to do linear IC design. I helped out and got better at learning and found a couple of disaster areas, too. Which I was able to fix. After that I made some more designs and got more into writing columns for Electronic Design Magazine.

What has been your favorite project?

The 4701 was my favorite because it led to not just a 10 kilohertz voltage-frequency but 100 kHz and then a megahertz and it was ultra linear. That was once of my better projects and it was over 40 years ago. But I worked on a lot of other projects that I truly enjoyed.

What are you currently working on?

I am doing some work, some consulting, and some contracting. I work on high precision current sources, high power. I have been having fun recently with audio amplifiers that are more linear than 0.1 parts per million. That is a little challenging. I do not need an Audio Precision; they won’t look at the signals I am looking at. I can see below .1 parts per million, in fact I can see below .02. I did quite well with that. I use a scope for the set up when testing it. I can use either Agilent or Tektronix but I need to use an old fashioned analog scope because I do not think most digital scopes will let you do what I am doing. With a digital scope there are certain things you cannot do. You cannot be certain you saw something. AN-1485 is a 20-page application note on how to measure below a part per million. Lots of op amps are below a part per million but when you get below that, you cannot just use an Audio Precision because it stops at about 3 parts per million. I figured out how to get it below .01 parts per million but people cannot normally hear that. I did a good 3 hour lecture at the AES in San Francisco 4 years ago about Audio. There are things you cannot hear that I can measure and there are things that you can hear that I cannot measure. We had a lot of fun with that.

What challenges do you foresee in our industry?

Well I see a lot of digital stuff that is insane, and I have no Idea. There is still some analog stuff that can be pretty good. You can have 100,000 engineers graduating in China that have no idea of a creative process or critical thinking so I would like to think that we are pretty good in this area, but we cannot lead forever.

Storm Peterson said “Predicting is very hard – - especially about the future.”

I am not good at foreseeing the future.

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