Bob Widlar
Robert John Widlar was an American electronics engineer and a designer of linear integrated circuits.
Early years
Widlar was born November 30, 1937, in Cleveland to parents of Czech, Irish and German ethnicity. His mother, Mary Vithous, was born in Cleveland to Czech immigrants Frank Vithous and Marie Zakova. His father, Walter J. Widlar, came from prominent German and Irish American families whose ancestors settled in Cleveland in the middle of the 19th century. A self-taught radio engineer, Walter Widlar worked for the radio station and designed pioneering ultra high frequency transmitters. The world of electronics surrounded him since birth: one of his brothers became the first baby monitored by wireless radio. Guided by his father, Bob developed a strong interest in electronics in early childhood.Widlar never talked about his early years and personal life. He graduated from Saint Ignatius High School in Cleveland and enrolled at the University of Colorado at Boulder. In February 1958 Widlar joined the United States Air Force. He instructed servicemen in electronic equipment and devices and authored his first book, Introduction to Semiconductor Devices, a textbook that demonstrated his ability to simplify complex problems. His liberal mind was a poor match for the military environment, and in 1961 Widlar left the service. He joined the Ball Brothers Research Corporation in Boulder to develop analog and digital equipment for NASA. He simultaneously continued studies at the University of Colorado and graduated with high grades in the summer of 1963.
Achievements
Widlar invented the basic building blocks of linear ICs including the Widlar current source, the Widlar bandgap voltage reference and the Widlar output stage. From 1964 to 1970, Widlar, together with David Talbert, created the first mass-produced operational amplifier ICs, some of the earliest integrated voltage regulator ICs, the first operational amplifiers employing single capacitor frequency compensation, an improved LM101 with FET internal current control, and super-beta transistors. Each of Widlar's circuits had "at least one feature which was far ahead of the crowd" and became a "product champion" in its class. They made his employers, Fairchild Semiconductor and National Semiconductor, the leaders in linear integrated circuits.Already a "legendary chip designer" at the age of 33, Widlar voluntarily retired into a hideout in Mexico and became "the Valley's most celebrated dropout." Four years later he returned to National Semiconductor as a contractor and produced a series of advanced linear ICs, including the first ultra-low-voltage operational amplifier with precision 200mV voltage reference.
Widlar's eccentric, and outspoken personality, and his bohemian lifestyle made him the enfant terrible of Silicon Valley. He is remembered in legends, myths and anecdotes that are largely true. According to Bo Lojek, author of History of Semiconductor Engineering, he was "more artist than an engineer... in the environment where Human Relations Departments define what engineers can and cannot comment about, it is very unlikely that we will see his kind again."
Fairchild Semiconductor (1963–1965)
Work at Bell Research brought Widlar in contact with Jean Hoerni and Sheldon Roberts, the creators of radiation hardened transistors and co-founders of Fairchild Semiconductor. Widlar decided to move to a semiconductor manufacturing company, and in 1963 Jerry Sanders, a Fairchild Semiconductor salesman, provided him the opportunity. According to Thomas Lee, Fairchild also wanted to have Widlar on board, and breached professional ethics by recruiting a key employee of their customer. In September 1963 Widlar was invited for an interview with Fairchild research and development manager Heinz Ruegg. Widlar arrived at the interview intoxicated, and frankly told Ruegg what he thought about Fairchild's analog circuits: "What they are doing is bullshit". Widlar was sent to another interview with the company's Applications Engineering division, which was based in Mountain View, California. The division head, John Hulme, hired Widlar despite objections from the first round interviewers. Widlar's first assignment at Fairchild targeted IC reliability through adjustments in fabrication processes. This early work, directed by process engineer David Talbert, reduced the cost of the planar process and made possible development of monolithic linear ICs. Widlar, who formally reported to John Barrett, proved himself capable of quickly improving Barrett's own designs and very soon squeezed his nominal boss out of the company.In 1963 Fairchild's analog IC lineup, designed to military specifications, consisted of three amplifier circuits. Before Widlar, Fairchild's engineers had designed analog ICs in a style not unlike conventional circuits built with discrete devices. Despite realizing early on that this approach was impractical, owing to the severe limitations of the early planar process, they had not devised working alternatives. When the original schematic required resistor values that were too low or too high for the planar process, designers often had to resort to the use of external nichrome thin film resistors. The resulting hybrid ICs performed poorly and were prohibitively expensive. In response, Fairchild's R&D chief Gordon Moore directed the company to favor digital integrated circuits, which were simpler and also promised high production volumes. Widlar opposed this strategy and held digital electronics in low esteem: "every idiot can count to one". Talbert shared Widlar's belief and became his closest ally in the company.
Widlar was a hard person to work with, but the few men and women who could, like Talbert and Jack Gifford, joined his inner circle for life. Widlar and Talbert closely guarded their trade secrets and kept unwanted co-workers out of the loop. Gifford, one of those accepted by Widlar and Talbert, said that Widlar "would almost talk to nobody and he would only talk to me on, you know, if I could get him in the right mood. And he was still secretive as hell". Talbert pushed Widlar's experimental orders through his plant at top speed, saving his partner four weeks on every batch at the expense of other orders. Former Fairchild photographer Richard Steinheimer said in 1995: "Talbert handling the fabrication and Widlar handling the design, they ruled the world and led the world in linear integrated circuits for a couple of decades." Fairchild executive Don Valentine said in 2004: "This was a phenomenal duo of highly eccentric – or whatever the word is beyond eccentric – individuals".
μA702 and μA709
Widlar soon grasped the benefits and drawbacks of the planar process: It provided matched components at all temperatures, but these components possessed parasitic capacitance not present in discrete parts, and the process imposed severe constraints on the practical values of resistors and capacitors. He summarised these design rules in a maxim: "Do not attempt to replicate discrete designs in integrated circuit form". Armed with this strategy and Hung-Chang Lin's theory of compensated devices, he designed the industry's first true linear integrated circuit, and the first monolithic operational amplifier, the μA702.Widlar dispensed with hybrid technology, and used only diffused resistors formed within the silicon die. Each of the nine NPN transistors was sized and shaped according to its function, contrary to an earlier, arbitrary practice of employing standard minimal-area patterns. Widlar introduced three innovations: Interfacing a long-tail with a single-ended stage without losing half of the gain, shifting the DC level using only NPN transistors, and providing optional frequency compensation with an external capacitor. Such compensation increased the bandwidth of the device to 25–30 MHz, an unprecedented breakthrough for monolithic amplifiers at that time. Widlar did not consider the μA702 prototype good enough for production, but Fairchild decided otherwise and rushed the chip into production in October 1964. The device set the direction for the industry for decades, despite limited common-mode range, weak output drive capabilities, and a price of $300. According to Jack Gifford, the top management of Fairchild noticed the novelty and learned of Widlar's existence only after receiving enthusiastic feedback from the market.
The μA709, which followed the compromised μA702, became a technical and commercial success. Widlar increased the μA709's voltage gain tenfold over that of the μA702, and improved output performance with a push-pull output stage, although the output lacked protection against short circuits. The input stage was governed by a Widlar current source which allowed generation of low bias currents without the need for area-consumptive high-value resistors. The transistors were equipped with beta-compensation resistors to reduce the effects of inevitable mismatch. Fairchild R&D staff spoke against Widlar's decision to employ lateral PNP transistors. Widlar locked himself up for 170 hours of continuous experimental work and came out with a robust design that blended two resistive diffusion areas into a usable lateral PNP device.
The μA709 was introduced in November 1965 and became Fairchild's revolutionary flagship product. For a few years, Fairchild was the leader in the field of linear ICs. Demand for its products exceeded its production capacity by a factor of ten; Fairchild's circuits were sold out for two years in advance. Gifford, one of the few men who fully understood Widlar and his work, contributed to the market boom by introducing a dual in-line package. According to Don Valentine, "at one point in time were responsible – one designed them and one made them – for more than eighty percent of the linear circuits made and sold in the world". None of Fairchild's competitors came close to matching its status in the market. Fairchild patented Widlar's innovations but never licensed them and never enforced their rights in court. Competitors created clones of μA709 but only Philco succeeded in producing one that fully matched the original.