Bob Widlar, Silicon Valley’s Earliest Crusader for Analog IC Design

April 19, 2022 by Jake Hertz

Bob Widlar was a rebel with a cause—an analog IC design cause.

The hall of engineering fame often remembers historic names like Michael Faraday, Gustav Kirchhoff, and James Clerk Maxwell. But among these names, few offered as much flare and practical innovation as Bob Widlar (1937–1991), one of the most prolific circuit designers of early Silicon Valley.


Bob Widlar

Bob Widlar is remembered as a "legendary chip designer,"  founding the Widlar current source, the Widlar bandgap voltage reference, and the Widlar output stage. Image (modified) used courtesy of Hackaday

Working among engineering legends, like the founders of Fairchild Semiconductor, Widlar has been described as “more artist than engineer.” With his pioneering discoveries spanning the µA702, µA709, µA710, LM100, LM101, LM107, LM108, and LM10 among many others, Widlar revolutionized analog IC design in modern engineering. 


Early Life and Education

Robert John ("Bob") Widlar grew up in Cleveland, Ohio, where his father worked as a radio engineer. At the age of 15, Widlar began his life-long career in electronics like many tinkerers of his time: he repaired radio and TV sets.

In 1958, Widlar joined the Air Force, where he was placed in charge of teaching his fellow servicemen about electronic equipment. One yearly performance review described Widlar as being “head and shoulders above the average technicians” because he wouldn't settle for mediocrity in his performance and constantly strived for perfection.

Following his service, Widlar graduated from the University of Colorado in 1962 with a bachelor of science in electrical engineering. During this time, he also worked with the Ball Brothers Research Corporation to help develop analog and digital equipment for NASA. He then went on to join Fairchild Semiconductor in 1963.


An Analog Innovator in a Digital Age

Widlar is most widely remembered for his work with analog monolithic integrated circuits (ICs). He was the first person to develop a solution for the limitations of the planar process when he realized ICs could not be designed in the same way as discrete circuits.

His unique approach to IC design culminated with the µA702, the first linear IC operational amplifier. While this op-amp was not initially well-received because of odd supply voltages, low input/output swings, low gain, and other strange characteristics, the µA702 heavily influenced subsequent IC design trends. 


Widlar wasn’t a fan of digital circuits

As a leader of analog design, Widlar wasn’t a fan of digital circuits. Image (modified) used courtesy of Fran Hoffart and Computer History


Soon after, Widlar introduced the µA709, another op-amp that was notably improved from the 702: it boasted higher gain, greater input/output ranges, lower input current, higher output current, and used symmetrical power supplies. The 709 is regarded as an IC op-amp classic and marks a milestone as the first widely-used monolithic IC op-amp. 


The µA709 monolithic IC op-amp

The µA709 monolithic IC op-amp. Image used courtesy of Op Amp History


In 1965, Widlar left Fairchild to work at National Semiconductor. While there, he released his design for the industry’s first high-power voltage regulator, the LM109. This finding came at a time when engineers hotly debated whether it was possible to develop a high-power regulator on a single chip. 

Widlar, established as an engineering genius in 1969, wrote a paper settling the debate, claiming temperature swings and packaging limitations made the device impossible. The industry took his word for it and stopped all efforts to build such a device. However, in 1970, Widlar shocked his contemporaries with the 20-W LM109, the industry’s first high-power voltage regulator. The device included all of the features Widlar had claimed were impossible just one year prior. 

Widlar's innovations also formed the foundation for modern bandgap voltage reference circuits, a staple in analog design today. 


An Engineering Prankster at Heart

Beyond his technical contributions, Widlar is remembered for his infamously irreverent attitude and workplace pranks. Once when National Semiconductor reduced its lawn maintenance budget, Widlar brought a sheep in the back of his convertible Mercedes-Benz to work to “mow” the lawn. 


Widlar with sheep

Widlar brought a sheep to "mow" the lawn of National Semiconductor. Image used courtesy of Fran Hoffart and Computer History

Widlar also famously built a so-called hassler circuit that emitted a high-pitched tone when people spoke loudly in the office. The device picked up the audio of a person's voice and played back the sound in a converted high-frequency squeal. The pitch would grow louder if a person raised his or her voice, and conversely, the circuit would stop ringing when a person stopped talking—getting Widlar's point across loud and clear.  

Widlar was also known to smash faulty components or dysfunctional prototypes with a sledgehammer, which he affectionately dubbed the "Widlar-izer."  


Lasting Legacy

Through both his direct attitude and his innovative hardware designs, Widlar is often remembered as an embodiment of the counter-culture of 1960s and 1970s Silicon Valley.

After retiring from National Semiconductor, Widlar moved to Mexico where he later died from a heart attack at the age of 53.  When everything was said and done, Widlar’s legacy included eight patents and landmark designs that laid the foundation for analog IC design as we know it.

Today Widlar is widely considered the “father of analog monolithic integrated circuits” and his body of work has been recognized through his induction into the National Inventors Hall of Fame.

  • Z
    zazeyay April 24, 2022

    Innovative, admirable engineer, and he sounds like he was fun.

    I am a teacher, and could use a “Hassler Circuit” a practical, direct feedback system! Are there any design plans available?

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  • J
    jrb_sland April 27, 2022

    God bless Mr. Widlar.  His LM10 solved a number of problems for me in the late 1970s when I was designing/constructing constant-current power supplies for tungsten-filament lamps used in various cameras, printers & test equipment in the {analog silver halide} movie business.  Its 200 mV super-stable voltage reference plus an uncommitted opamp needed only a low-value current sense resistor & a couple of generic resistors to then drive any series power transistor as the pass element.  The advantage of current regulation is that it automatically compensates {within reasonable limits}  for varying contact resistance in lamp sockets, on-off switches & the like. 
    EECO had recently {1976} introduced their line of thumbwheel-selected substitutes for rotary analog potentiometers, so that I could design regulators with machine-operator-adjustable outputs that only required the user to select a particular two-digit number rather than watching an analog voltmeter to set the desired VOLTAGE {!!} at the lamp socket terminals, which doesn’t deal with contact resistance.

    The LM10 is still an actively available chip.

    Good designs last forever!  Love the sheep story!

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