I think the above image is the perfect introduction to Bob Widlar, I couldn't describe him any better with words if I tried and besides, Engineer's much prefer to communicate with pictures over words.
The Introduction of the Op-Amp
Bob was a legendary engineer in every sense of the word, considered to be one of the greatest hardware engineers of all time. He was also rather quirky! Who doesn't love a quirky engineer :P Many considered him more of an artist than an engineer, and really at the time there was a lot of artistry to analog IC design. One of his many famous designs is the Fairchild uA702, the FIRST linear IC operational amplifier released in 1964, that's right he is the inventor of the first commercial op-amp a category of device which is still ubiquitously used!
Widlar Current Source
The Widlar current source is a slight modification of the current mirror which adds an emitter degeneration resistor for the output transistor which allows the current source to source low currents using only moderate resistor values.
The LM109 was the industry’s first high-power voltage regulator.
The Hassler Circuit
Bob didn't like loud noises, and so he dealt with it by inventing a circuit which would detect the audio, convert it into a high frequency, and playback the converted sound.
If Bob spent an entire day on a circuit which never worked he would take the part over to an anvil in the office and give it a proper beating! Let's bring it back :P
As you can see from the above, Bob left quite an impression on the industry and those around him. The best way for us to develop a feel for how Widlar really was as a person is from anecdotal evidence such as the personal accounts below:
“Bob was a fiercely independent individual, very happy to be by himself, and he did everything in a stunning way, which was absolutely natural to him, but completely weird to so-called ‘normal people’.” History of Semiconductor Engineering
“How do you Widlarize something? You take it over to the anvil part of the vice and you beat on it with a hammer, until it is all crunched down to tiny little pieces, so small that you don’t even have to sweep it off the floor. It sure makes you feel better. And you know that that component will never vex you again.” ~ Bob Pease
"Once upon a time, when Analog designers came at work by horse and let it in the grass of the Company or in VW mini bus and slept in the parking to not loose Time.
… Widlar (current miror) was one of them." - Christian Terrier (Retired. Semiconductor Veteran. Chip Design"
"He was one of the « spécial » guys, already thinking California hypotypose way of Life." - Christian Terrier (Retired. Semiconductor Veteran. Chip Design"
"There was a légend about Bob Widlar. When he was older (40), he was still living like an homeless and when he needed some money he came back to fairchild to design an new opamp … and after disapeared in the nature until he needs again money.
Unfortunaly he passed away very early (before 60)." - Christian Terrier (Retired. Semiconductor Veteran. Chip Design"
"Widlar was a pure genius. He created several opamps that revealed to be milestones (after the 741, he created the 108). But he also invented the bandgap reference.
And he created the 3 terminals voltage regulators that he pushed to 10 Amps..." - Jean-Francois Debroux (Senior Analog IC Designer)
On the LM741 "I think he needed a feedback loop to control the input stage bias current. Because of the input NPN follower aimed at reducing bias current and make it more controllable thanks to the NPNs beta, the differential common base PNPs pair base voltage has to be kept 1.4 V below input common mode. This is what the loop does. Q8-Q9 mirror copies input stage current and "compares" it to Q10 current. Should input common mode increase, Q8-Q9 current would increase, pulling Q3-Q4 base up to follow, reducing current.
Widlar was a genius" - Jean-Francois Debroux (Senior Analog IC Designer)
It is important to never forget the human's behind the inventions we take for granted, at the end of the day all technology was once invented by humans.