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Transistor–transistor logic (TTL) is a logic family built from bipolar junction transistors.Its name signifies that transistors perform both the logic function (the first "transistor") and the amplifying function (the second "transistor"), as opposed to earlier resistor–transistor logic (RTL) and diode–transistor logic (DTL).
Current mode logic (CML), or source-coupled logic (SCL), is a digital design style used both for logic gates and for board-level digital signaling of digital data. The basic principle of CML is that current from a constant current generator is steered between two alternate paths depending on whether a logic zero or logic one is being represented.
A multiple-emitter transistor is a specialized bipolar transistor mostly used at the inputs of integrated circuit TTL NAND logic gates. Input signals are applied to the emitters . The voltage presented to the following stage is pulled low if any one or more of the base–emitter junctions is forward biased, allowing logical operations to be ...
His patent also showed how the Schottky transistor could be used in DTL circuits and improve the switching speed of saturated logic designs, such as the Schottky-TTL, at a low cost. In 1971, Texas Instruments introduced the 74S TTL logic family with Schottky diodes. Later, it was included in the 74LS, 74AS, 74ALS, 74F TTL logic families too.
In electronics, emitter-coupled logic (ECL) is a high-speed integrated circuit bipolar transistor logic family. ECL uses an overdriven bipolar junction transistor (BJT) differential amplifier with single-ended input and limited emitter current to avoid the saturated (fully on) region of operation and the resulting slow turn-off behavior. [ 2 ]
Diode–transistor logic improved the fan-out up to about 7, and reduced the power. Some DTL designs used two power supplies with alternating layers of NPN and PNP transistors to increase the fan-out. Transistor–transistor logic (TTL) was a great improvement over these. In early devices, fan-out improved to 10, and later variations reliably ...
See also: Diode logic § Active-high AND logic gate Open-collector buffers connected as wired AND.. The wired AND connection is a form of AND gate.When using open collector or similar outputs (which can be identified by the ⎐ symbol in schematics), wired AND only requires a pull up resistor on the shared output wire.
An inverter circuit outputs a voltage representing the opposite logic-level to its input. Its main function is to invert the input signal applied. If the applied input is low then the output becomes high and vice versa. Inverters can be constructed using a single NMOS transistor or a single PMOS transistor coupled with a resistor. Since this ...