Bob Widlar

1937-1991

The hard-drinking analog genius who invented the building blocks of linear ICs (the current source, the bandgap reference, the first integrated op-amps and voltage regulators) that sit inside nearly every chip you use.

Robert John Widlar was born in 1937 in Cleveland, Ohio. His father was a self-taught radio engineer who built UHF transmitters, and electronics surrounded Bob from birth. He graduated from the University of Colorado in 1963 after a stint in the Air Force, where he taught electronics and wrote his first textbook. Then he walked into Fairchild Semiconductor and changed analog design forever, arriving at his job interview drunk and bluntly telling the research manager that the company's analog circuits were nonsense.

Widlar's key insight was that you cannot just copy circuits built from discrete parts onto a silicon chip. The early planar process made decent resistors hard to fabricate but matched transistors easy, so he invented new circuit structures that played to silicon's strengths. The Widlar current source generates a tiny, stable bias current without needing the huge resistors a naive design would demand. Paired with David Talbert, who pushed his experimental chips through the fab in record time, Widlar produced the first true monolithic operational amplifier (the uA702) and then the wildly successful uA709, putting Fairchild at the top of the linear IC world.

He jumped to National Semiconductor in 1965, where he designed the first integrated voltage regulators (the LM100 and LM105) and a string of landmark op-amps including the LM101. His most enduring trick came at the end of the decade: he converted his current source into a bandgap voltage reference, a circuit that produces a rock-steady reference voltage (around 1.25 volts) that barely drifts with temperature. He combined a power transistor and a precise reference on one die to make the LM109 regulator, and the sub-bandgap reference in his later LM10 ran on a supply as low as 1.1 volts.

Widlar's blocks are everywhere in modern hardware. Bandgap references set the voltage that ADCs and DACs measure against, and they anchor the regulators on your power rails. Current mirrors and current sources bias nearly every analog stage and op-amp. When the regulator on your board holds a clean 3.3 volts, or your ADC reading is accurate because its reference does not wander with temperature, you are using circuits Widlar invented. He retired to Mexico at 33, then kept consulting; people said he and Talbert at one point were responsible for over eighty percent of the linear circuits sold in the world.

Fun facts

Widlar's design philosophy fit on a bumper sticker: do not attempt to replicate discrete designs in integrated circuit form. Silicon made big resistors expensive but matched transistors cheap, so he built clever circuits like the current mirror that traded scarce resistors for plentiful transistors.
He was famously eccentric. He practiced widlarizing, methodically smashing a faulty prototype with a sledgehammer, installed devices that emitted painful tones when people talked too loud near his lab, and once traced electromagnetic interference to the San Jose airport tower and phoned them to demand they shut down the transmitter.
He cashed in his stock options and retired to Puerto Vallarta at age 33, becoming Silicon Valley's most celebrated dropout, then returned years later as a contractor to design the LM10 and LM12, chips so good that no competitor matched the LM10 for a decade.