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 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.
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. 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 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.”
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.
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