Evolution of TTL family. • ECL. • CMOS family and its evolution. • Overview. 2 Diode-Transistor Logic (DTL) . Scaling capabilities (large integration all MOS). Logic Families – TTL, CMOS, ECL. 10 January TTL(Transistor Transistor Logic); CMOS (Complementary MOS); ECL (Emitter Coupled Logic). DTL. (Diode Transistor Logic). – Use diodes and transistors. – Input is fed TTL. ( Transistor-Transistor Logic). – Use all transistors totem pole output. ECL. ( Emitter Coupled Logic). – Non saturated logic/Current mode logic. MOS Logic Families DTL. HTL. TTL. ECL. MOS. CMOS. Basic Gate. NOR. NOR. NAND. NAND.

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From Wikipedia, the free encyclopedia. A “logic family” may also refer to a set of techniques used to implement logic within VLSI integrated circuits such as central processorsmemories, or other complex functions. Archived from the original on These devices only work with a 5V power supply. The diode-transistor logic, also termed as DTL, replaced RTL family because of greater fan-out capability and more noise margin.

Logic Families – Digital Electronics

The required silicon area for implementing such digital CMOS functions has rapidly shrunk. ICs of different families tttl sometimes also be directly connected together, but may require some extra circuitry at the interface of the two IC families to maintain compatibility.

A variant of DTL called “high-threshold logic” incorporated Zener diodes to create a large offset between logic 1 and logic 0 voltage levels. RTL resistor-transistor logic and DTL diode-transistor logicsuccessfully used in early computers were superseded by TTL transistor-transistor logicwhich became the dominant technology.

Texas Instruments introduced the series TTL family in In computer engineeringa logic family may refer to one of two related concepts.

When the gate switches states, current is drawn from the power supply to charge the capacitance at the output of the gate. Retrieved from ” https: Powered by Create your own unique website with customizable templates. Wikipedia articles needing clarification from July The logic gates introduced in Module 2.


If any of input of MOS is left cmoss, the open input terminal which has very high input impedance may take any stray electric charge as input and can develop extreme dangerous high voltage which can damage the device and may also harm the edl handling the device.

A family of diode logic and diode—transistor logic integrated circuits was developed by Texas Instruments for the DC Minuteman II Guidance Computer inbut these devices were not available to the public. Not shown are some early obscure logic families exl the early s such as DCTL direct-coupled transistor logicwhich did not become widely available.

Texas Instruments soon introduced its own family of RTL. The extremely small capacitance of the on-chip wiring caused an increase in performance by several orders of magnitude. A short list of the most important family designators of these newer devices includes:. Thus, none of the un-used inputs of MOS device should be left unconnected. Analog, and Mixed-SignalMarcel Dekker, pp. The diode will conduct only when corresponding input is LOW.

Diode DA is replaced by collector-base junction of T1. It could be used both with logic devices which used 3. All electrical circuits must consume some power, and any change in the voltages and currents in that circuit must take at least some time. Propagation delay is the time taken for a two-input NAND gate to produce a result after a change of state at its inputs.

Early transistorized computers were implemented using discrete transistors, resistors, diodes and capacitors. The German physicist Walter H. Learn about electronics Digital Electronics. If both the inputs are LOW, then both the transistors are in cut-off i.

Diode DB is replaced by emitter-base junction of transistor labeled T2. Thus, to interface this logic family with other, a translator circuit is needed which converts negative voltages to compatible positive voltage levels.


Here, p-channel devices are in series and n-channel devices are in parallel. Thus, voltage Vcc appears at output I. Even for storage of device, all pins must be shorted. Although each gate only dissipates a few milliWatts, the heat generated within a single cmks integrated LSI circuit containing tens of thousands of transistors could potentially quickly destroy the IC.

Module 3.1

Gates built with Schottky transistors use more power than normal TTL and switch faster. ECL logic family implements the gates in differential amplifier configuration in which transistors are never driven in the saturation region thereby improving the speed of circuit to a great extent.

These two logic families were not readily compatible; apart from the differences in supply voltage and speed, they were not particularly pin compatible, as illustrated in Fig.

Transistors T3 and T4 are emitter-followers used for DC level-shifting of output voltages. Many motherboards have a voltage regulator module to provide the even lower power supply voltages required by many CPUs. Many logic families were produced as individual components, each containing one or a few related basic logical functions, which could be used as “building-blocks” to create systems or as so-called “glue” to interconnect more complex integrated circuits.

Variations on the basic TTL design are intended to reduce these effects and improve speed, power consumption, or both.

These devices usually ran off a 15 volt power supply and were found in industrial control, where the high differential was intended to minimize the effect of noise. The integrated injection logic IIL or I 2 L uses bipolar transistors dt, a current-steering arrangement to implement logic functions.

Static Dynamic Domino logic Four-phase logic. Why these different families exist dates back to the s when groups of dt, ICs using different technologies first became available.