7400 series

The 7400 series of TTL integrated circuit SSI devices were historically important as the first widespread family of IC devices. Modern variants of the family are still used today for "glue logic".

They were constructed using bipolar transistors, although some newer sub-series use CMOS technology. These circuits provide higher speed but consume more power than the 4000 series of CMOS devices. TTL devices are also limited to a set voltage, typically 5V. The family contains many hundreds of devices that provide everything from basic logic gates to special purpose bus transceivers and Arithmetic Logic Units (ALU). The 7400 series is numerically and electrically equivalent to the 5400 series. The 5400 series are milspec rated devices for use in extreme conditions.

• 7400 series subfamilies
  • S - Schottky (obsolete)
  • LS - Low Power Schottky
  • AS - Advanced Schottky
  • ALS - Advanced Low Power Schottky
  • F - Fast (now obsolete family used in 1970s era computers)
  • C - CMOS (obsolete)
  • HC - High speed CMOS
  • HCT - High Speed CMOS, TTL Compatible

The 74L family is a relatively low-power, but slower version of the 74 family.

The 74H family is a high threshold version of the 74 family, designed for use in noisy industrial environments. Both of these variants of the 74 family were obsoleted by later versions and CMOS logic families.

The 74S family, using Schottky circuity, uses more power than the 74, but is faster. The 74LS family of ICs is a lower-power version of the 74S family, with slightly higher speed but lower power than the original 74 family; it became the most popular variant once it was widely available.

The 74F family was introduced by Fairchild Semiconductor and adopted by other manufacturers; it is faster than the 74, 74LS and 74S families.

History

The 7400 NAND gate was the first one in the series. It originally retailed for nearly $1000 per package of four gates, in 1962, when a well-paid engineer earned $9500/year.

The computer for the Minuteman II missile used integrated circuits in such large quantities that the prices fell to only $15 per package of four gates, paying for the difficult new lithographic assembly lines, and enabling the sharply-reducing prices of the modern digital computer.

Currently (2003), individual chips can be purchased for approximately $0.25 each, depending on the particular chip. Purchased in bulk the price per unit falls to a few pennies per package.