Intel 4004 processors
Introduction: November 1971
The 4004, a 4-bit central processing unit (CPU) released by Intel Corp., is widely considered to be the world's first commercial single-chip microprocessor. The Intel 4004, naturally, is one of world's most sought-after collectable/antique chips.
The 4004 was released in 16-pin CDIP packaging on November 15th, 1971. It was the first computer processor designed and manufactured by chip maker Intel, which previously made semiconductor memory chips. The chief designers of the chip were Ted Hoff and Federico Faggin of Intel and Masatoshi Shima of Busicom (later of Zilog).
This revolutionary microprocessor, measuring 1/8th by 1/6th of an inch - the size of a fingernail - delivered the same computing power as the first electronic computer, the ENIAC, built in 1946, which filled an entire room and used 18,000 vacuum tubes.
Originally designed for the Japanese company Busicom to be used in their line of calculators (instead of the complex special purpose calculator chipset that Busicom had designed themselves and brought to Intel to have made, which Intel determined was too complex to make with the technology they had at the time), the 4004 was also provided with a family of custom support chips. The 4004 circuit was built of 2,300 transistors, and was followed the next year by the first ever 8-bit microprocessor, the 3,300 transistor 8008 (and the 4040, a revised 4004).
All of Intel's 4004 datasheets, including the very first datasheet from November 1971, clearly indicate that the minimum clock period is 1350 nanoseconds, which results in a maximum clock speed of 740KHz. Unfortunately, many apparently reputable web pages and other sources list an incorrect clock speed of 108KHz; even Intel's own pages on the 4004's history say this. The 4004's minimum instruction cycle time is 10.8 microseconds (8 clock cycles), and it seems most likely that someone in the past confused this with a clock speed. This error has now propagated very widely.