Transistor-Transistor Logic


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transistor-transistor logic

[tran′zis·tər tran′zis·tər ′läj·ik]
(electronics)
A logic circuit containing two transistors, for driving large output capacitances at high speed. Abbreviated T 2L; TTL.

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.
References in periodicals archive ?
The device accepts Low Voltage Positively Referenced Emitter Coupled Logic (LVPECL), Low Voltage Transistor-Transistor Logic (LVTTL), Low Voltage Complementary Metal Oxide Semiconductor (LVCMOS), High Speed Transceiver Logic (HSTL), Current Mode Logic (CML) or Low Voltage Differential Signaling (LVDS) signals, and translates them to differential -2.
The MC100EP196 accepts ECL, Complimentary Metal Oxide Semiconductor (CMOS) and Transistor-Transistor Logic (TTL).
DMA Direct Memory Access EDA Electronic Design Automation EPIC Embedded Programmable Interrupt Controller HW/SW Hardware and Software PCI Peripheral Component Interconnect SOC Systems-on-Chip TTL Transistor-Transistor Logic