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'''Transistor–transistor logic''' is the circuit type inside the most widespread early [[integrated circuit]] family; it replaced the earlier [[diode–transistor logic]]. The name is derived from the fact that both logic as well as signal-amplification were performed by [[transistor]]s.

The earliest TTL chips are classed as [[SSI]], but eventually TTL chips ranged up to the largest [[MSI]]. Building larger chips out of TTL was not feasible, as TTL logic tends to dissipate fairly large amounts of heat, which is what led to its eventual superceding by [[Metal Oxide Semiconductor|MOS]].

One extremely popular line of TTL chips was the [[74 series]], produced by [[Texas Instruments]]; many other manufacturers eventually produced number-compatible TTL chips of their own (so that, say, a 7400 from Motorola was a pin-compatible replacement for the TI chip).

Most computers from the late 1960s through to the middle 1970s were produced entirely in TTL (although its use in such ways continued until the early 1980s - e.g. the [[IBM 3081]] was built out of TTL), and TTL continued to be widely used for the 'glue' logic between larger [[VLSI]] chips until the 1990s, when the lower voltages used with [[CMOS]] made them obsolete.

==External links==

* [http://en.wikipedia.org/wiki/Transistor–transistor_logic Transistor–transistor logic TTL article on Wikipedia - has comprehensive coverage of the topic]