meaning of transistor logic
1. Transistor-Transistor Logic TTL A common semiconductor technology for building discrete digital logic integrated circuits. It originated from Texas Instruments in 1965. There have been several series of TTL logic: 7400:10 ns propagation time, 10 mW/gate power consumption, obsolete; 74L00:Low power: higher resistances, less dissipation 1 mW, longer propagation time 30 ns; 74H00: High power: lower resistances, more dissipation: less sensitivity for noise; 74S00: Schottky-clamped: faster switching 3 ns, 19 mW by using Schottky diodes to prevent the transistors from saturation; 74LS00: Low power, Schottky-clamped 10 ns, 2 mW; 74AS00: Advanced Schottky: faster switching, less dissipation, 1. 5 ns, 10 mW; 74ALS00: Advanced Low power Schottky 4 ns, 1. 3 mW. For each 74xxx family there is a corresponding 54xxx family. The 74 series are specified for operation at 0 - 70 C whereas the 54 military series can operate at -55 - 125 C See also CMOS, ECL. TRANSIT
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