Computer History MuseumSemiconductor History

1974 - Digital Watch is First System-On-Chip Integrated Circuit

The Microma liquid crystal display (LCD) digital watch is the first product to integrate a complete electronic system onto a single silicon chip, called a System-On-Chip or SOC.

A System-On-Chip (SOC) integrated circuit incorporates all the electronic components, including analog and interface circuitry, required to implement a system on a single chip. The first SOC solution evolved from the $2,100 Hamilton Pulsar "Wrist Computer" digital watch unveiled on the Johnny Carson Show in 1970. Designed by George Thiess and Willy Crabtree at Electro-Data, Inc., the watch containing 44 chips and 4,000 bonding wires was notoriously unreliable until RCA engineers reduced the timekeeping circuitry to one chip. External transistors were still required to drive power-hungry light emitting diode (LED) displays. In 1972-73 Microma and Seiko introduced low-power liquid crystal displays (LCD) that extended battery life by orders of magnitude. Intersil co-founders John Hall and Jean Hoerni designed the Seiko chip.

The first true SOC appeared in a Microma watch in 1974 when Peter Stoll integrated the LCD driver transistors as well as the timing functions onto a single Intel 5810 CMOS chip. (1963 Milestone) TI’s single chip LCD watch, introduced at under $20 in 1976, started a battle of attrition with Timex and dozens of other semiconductor manufacturers who entered the market. National and TI were major players in the next SOC application, the electronic calculator, but both abandoned these low-end consumer products to Asian suppliers when prices dropped below $10.

Many ASIC vendors (1967 Milestone) addressed SOC opportunities in the 1990s by embedding microcontrollers (1974 Milestone) and DSPs (1979 Milestone) into system-level chips that enabled hand-held games and instruments, as well as speech processing, data communications, and PC peripheral products.

Contemporary Documents

Forrer, M.P. "Survey of Circuitry for the Wristwatches," Proceedings of the IEEE, Vol. 60, Issue 9 (Sept. 1972) pp. 1047-54.

More Information

Volk, Andrew M., Stoll, Peter A., Metrovich, Paul. "Recollections of Early Chip Development at Intel," Intel Technology Journal Q1 (2001).

Stephens, Carlene and Dennis, Maggie "Engineering Time: Inventing the electronic wristwatch" The British Journal for the History of Science Vol. 33, Issue 4 (Cambridge University Press, December 2000) pp. 477-497.

Trueb, Lucien F. "The Hamilton Pulsar: A Space Odyssey," WatchTime (April 2004) pp. 134-138.

Weaver, J. D. Electronic Clocks and Watches (London: Newnes Technical Books, 1982)