Each IC family has its own characteristics, limitations and advantages. There have been many improvements in logical families such as TTL and CMOS. Logic (DTL); Transistor-Transistor Logic (TTL); Emitter Coupled Logic (ECL). 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 Basic Logic Families indicate the type of logic circuit used in the IC. The main types of logic families are.

Author: Kazihn Marg
Country: Portugal
Language: English (Spanish)
Genre: Software
Published (Last): 2 May 2009
Pages: 42
PDF File Size: 9.27 Mb
ePub File Size: 15.99 Mb
ISBN: 833-3-18958-128-7
Downloads: 77533
Price: Free* [*Free Regsitration Required]
Uploader: Muran

The delay times are measured between the 50 percent voltage levels familiee input and output waveforms. 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. There is no power dissipation in CMOS. Comparator IC LM Although each gate only dissipates a few milliWatts, the heat generated within a single large-scale integrated Dihital circuit containing tens of thousands of transistors could potentially quickly destroy the IC.

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.

Digital Logic Design: IC Families Explained

Multivibrators Asymmetrical Square wave generator Bistable multivibrators Monostable multivibrator Sawtooth waveform generator Triangular waveform generator. RTL gates can be used as amplifiers as well to amplify small signals. Finite State Machines Topics. Three terminal adjustable Voltage regulator ICs. Medium scale integration MSI 12 to 99 no of gates 3.

The logic levels for ECL are normally Wikipedia articles needing clarification from July TTL uses bipolar transistors to construct its integrated circuits. The output circuit has also been modified in recent years and the the configuration is called “Totem pole”.


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. However the laws of physics, as presently understood, say that this is not possible.

Logic Families – Power, Speed and Compatibility

Material is molded plastic, epoxy, resin, or tdl. The following currents and voltages are specified which are very useful in the design of digital systems.

Some military applications pre-dated civilian use. Finite State Machines Also within each family, there is a range of voltages which may be high level or low level.

It is also considered to be one of the most reliable logic family today. The first diode—transistor logic family of integrated circuits was introduced by Signetics in CMOS logic gates use complementary arrangements of enhancement-mode N-channel and P-channel field effect transistor.

The required silicon area for implementing such digital CMOS functions has rapidly shrunk.

By using this site, you agree to the Terms of Use and Privacy Policy. While using this site, you agree to have read and accepted our terms of etl and privacy policy. The extremely small capacitance of the on-chip wiring caused an increase in performance by several orders of magnitude.

Several early transistorized computers e. Other such logic families, such as domino logicuse clocked dynamic techniques to minimize size, power consumption and delay. Many logic families were produced as individual components, each containing one or a few related basic logical functions, eecl could be used as “building-blocks” to create systems or as so-called “glue” to interconnect more complex integrated circuits.

These input signals are then inverted and amplified. The propagation delay time of the logic gate is taken as the average of these two delay times. All electrical circuits must consume some power, and any change in the voltages and currents in that circuit must take at least some time. These design styles can typically be divided into two main categories, static techniques and clocked dynamic techniques. In computer engineeringa logic family may refer to one of two related concepts.


Diode logic was used with vacuum tubes in the earliest electronic computers in the s including ENIAC.

Programmable Logic Devices Architectures When the gate switches states, current is drawn from the power supply to charge the capacitance at the output of the gate. They can also be used as an interface between digital and linear circuits. We will only discuss the basic TTL. Modified Precision Full Wave Rectifier.

Module 3.1

Sequential Logic Circuits CMOS chips often work with a broader range of power supply voltages than other logic families. Understand differences between logic families. Each family has its own characteristics, advantages and disadvantages.

A family has its own power supply voltage and distinct logic levels. Saturating type Precision HWR. Low-level input current, IIL: Online tutorials designed are mainly intended to understand the mls concepts of electronics engineering.

Digital Logic Design: IC Families Explained

Ideally logic gates should be able to change state immediately and consume little or no power. In fact, it is the fastest bi-polar circuit available today. The digital ICs are categorized as, 1. Motorola Semiconductor Products Inc. A whole range of newer families has emerged that use CMOS technology. Comparator as a function generator.