Transistor-transistor
logic, It is a common type of
digital circuit in which the output is derived from two
transistors. The first semiconductors using TTL were
developed by Texas Instruments in 1965. The term is
commonly used to describe any system based on digital
circuitry, as in TTL monitor.
With the rapid development of
integrated circuits (ICs), new problems were encountered
and new solutions were developed. One of the problems
with DTL circuits was that it takes as much room on the
IC chip to construct a diode as it does to construct a
transistor. Since "real estate" is exceedingly important
in ICs, it was desirable to find a way to avoid
requiring large numbers of input diodes.