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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ICs of a particular family generally use a common technology, but ICs in other families, using different technologies, usually have different input and output requirements, different supply voltages, and other parameters that affect the use of digital ICs. CMOS Complimentary Metal Oxide Semiconductor chips, designed for minimum mps, got faster and TTL families, using bipolar transistors for optimum speed, were developed that not only increased speed but also reduced power consumption.

The integrated injection logic IIL or I 2 L uses bipolar transistors in a current-steering arrangement to implement logic functions. The codes used vary between manufacturers, but package details are usually included on the IC datasheet. Hons All rights reserved. Some such logic families use static techniques to minimize design complexity. Diode DB is replaced by emitter-base junction of transistor labeled T2. Analog, and Mixed-SignalMarcel Dekker, pp. See static versus dynamic logic for some discussion on the advantages and disadvantages of each category.

Introduction year tyl when at least some of the devices of the family were available in volume for civilian uses.

Logic family – Wikipedia

The first diode—transistor logic family of integrated circuits was introduced by Signetics in However, because the logic thresholds of CMOS were proportional to the power supply voltage, CMOS devices were well-adapted to battery-operated systems with simple power supplies.

Hence this family of logic gates is modified to transistor-transistor logic i. The increase in portable battery powered electronic devices along with the ability of chip manufacturers to make the component parts of ICs much smaller also meant that power could be reduced and speed increased. By using this site, you agree to the Terms of Use and Privacy Policy.


Module 3.1

RTL family is characterized by poor noise margin, poor fan-out capability, low speed and high power dissipation. Thus, to interface this logic family with other, a translator circuit is needed which converts negative voltages to compatible positive voltage levels. These design styles can typically be divided into two main categories, static techniques and clocked dynamic techniques. Interconnecting any two logic families often required special techniques such as additional pull-up resistorsor purpose-built interface circuits, since the logic families may use different voltage levels to represent 1 and 0 states, and may have other interface requirements only met within the logic family.

Because CMOS and TTL families can now operate at similar speeds and similar power consumption, the 74HCT a CMOS sub-family compatible with TTL pinouts and voltage levels now makes it possible to easily interface both families within in a single design, so enabling the use of the best features of each family.

RTL resistor-transistor logic and DTL diode-transistor logicsuccessfully used in early computers were superseded by TTL transistor-transistor logicwhich became the dominant technology.

These devices only work with a 5V power supply. Texas Instruments soon introduced its own family of RTL. This means that the current draw of CMOS devices increases with switching rate controlled by clock speed, typically. The diodes D1, D2 and D3 are replaced by emitter-base junctions of a multiple-emitter transistor labeled T1. Learn about electronics Digital Electronics.

Logic family

It could be used both with logic devices which used 3. A typical 74 series IC is shown in Fig 3. Powered by Create your own unique website with customizable templates. Several techniques and design styles are primarily used in designing large single-chip application-specific integrated circuits ASIC and CPUs, rather than generic logic families intended for use in multi-chip applications.

For the same power dissipation, Schottky transistors have a faster switching speed than conventional transistors because the Schottky diode prevents the transistor from saturating and storing charge; see Baker clamp. The diode-transistor logic, also termed as DTL, replaced RTL family because of greater fan-out capability and more noise margin. Gates built with Schottky transistors use more power than normal TTL and switch faster.


A logic family of monolithic digital integrated circuit devices is a group of electronic logic gates constructed using one of several different designs, usually with compatible logic levels and power supply characteristics within a family. Transistor—transistor logic uses bipolar transistors to form its integrated circuits.

A large collector current of T1 is in such direction that it helps removing base charge of T2 and T3. Motorola Semiconductor Products Inc.

DTL was also made by Fairchild and Westinghouse. It must connected to ground or supply. If both transistors T1 and T2 are off i. A CMOS gate draws no current other than leakage when in a steady 1 or 0 state. A “logic family” may cmoos refer to a set of techniques used to implement logic within VLSI integrated circuits such as central processorsmemories, or other complex functions.

With HC and HCT logic and LS-TTL logic competing in the market it became clear that further improvements were needed to create the ideal logic device that combined high speed, with low power dissipation and compatibility with older logic families.

The required silicon area for implementing such digital CMOS functions has rapidly shrunk. If any of the diode is conducting i.

CMOS chips often work with a broader range of power supply voltages than other logic families. Note how CMOS speed has been increased and power reduced with the introduction of the 74HC High-speed CMOS although as the laws of physics demandpower consumption still increases, as the frequency at which they operate increases.


Logic Families – Power, Speed and Compatibility

Values are very typical and would vary slightly depending on application conditions, manufacturer, temperature, and particular type of logic circuit. The German physicist Walter H. The collector-base junction of T1 is back-biased and T1 operates in normal active region.