Robert Widlar inspects the LM10 mask layout circa 1977
Credit: National Semiconductor.

Analog, also called linear, circuits amplify and condition signals from continually varying phenomena such as sound, temperature, and radio waves. Because of the nearly infinite resolution required to process these signals, analog circuits demand high precision in design and manufacturing. Early analog circuit designs were paced by the operational amplifier (op-amp) concepts developed by Columbia University researcher Loebe Julie. George Philbrick exploited these in his vacuum tube K2-W op-amp for performing electronic signal integration in 1952. The first germanium transistor op-amp appeared in 1958 with silicon versions in 1960. Nexus Research Labs offered the first pre-configured op-amp modules in 1962 followed shortly by Burr-Brown and Philbrick Researches.

Amelco, Fairchild, RCA, TI, and Westinghouse - where H. C. Lin conceived the idea of on-chip component matching - developed early monolithic amplifiers. But the Fairchild µA702 op amp, created in 1964 by the team of process engineer Dave Talbert and designer Robert Widlar, was the first widely-used device. Their 1965 successor, the µA709, established a mass market for analog ICs. Talbert and Widlar moved to Molectro (later acquired by National) in late 1965 where they built a linear dynasty beginning with the LM101. Then in 1968 Dave Fullagar of Fairchild one-upped the LM101 by adding an internal compensating capacitor to deliver the µA741, the most popular op-amp of all time. Analog Devices' designers followed the basic 741 architecture for its first high-precision op-amp in 1971. Specialty analog IC manufacturers evolved extensive catalogs of amplifiers, comparators, data converters, power management devices, and numerous specialty circuits for automotive, consumer and communications applications.