Ecl logic families pdf

Rtlresistor transistor logic dtldiode transistor logic ttltransistor transistor logic eclemitter coupled logic cmoscomplementary metal. The equivalent of emittercoupled logic made from fets is called sourcecoupled logic scfl. Integrated circuits integrated circuits ics are chips, pieces of semiconductor material, that contain all of the transistors, resistors, and capacitors necessary to. Nov 07, 2017 prebook pen drive and g drive at teacademy. Design of a highspeed transistor for the aslt current switch pdf. It mentions ecl advantages and ecl disadvantages over ttl and cmos.

Resistortransistor logic rtl diodetransistor logic dtl emitter coupled logic ecl logic families can be classified broadly according to the technologies they are built with transistortransistor logic ttl cmos logic ttl and cmos logic family is most widely used ic technologies. Consequently, dctl gates have fewer components, are more economical, and are simpler to fabricate onto integrated circuits than rtl gates. Characteristics of logic families in digital electronics. Emitter coupled logic non saturated logiccurrent mode logic. The ecl families the ecl emitter coupled logic families, originated in the late 1950s and remain the fastest chips available, but consume more power, and because they use a negative power supply of 5. In electronics, emittercoupled logic ecl is a highspeed integrated circuit bipolar transistor logic family. Emittercoupled logic is based on the use of the currentsteering switch introduced in section 15. The equivalent of emittercoupled logic made out of fets is called sourcecoupled logic scfl. 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.

There are different families of logic gates in digital logic design. Termination of ecl devices with ef emitter follower output structure prepared by. Extension of mos inverter concepts to nor and nand gate is very simple. Digital logic families in digital designs, our primary aim is to create an integrated circuit ic. Within each family, several subfamilies of logic types are. The ecl emitter coupled logic families, originated in the late 1950s and remain the fastest chips available, but consume more power, and because they use a negative power supply of. Internal temperature and voltage compensated bias network. The concept was later refined by motorola and others to produce the still popular 10k and 100k ecl families. And8020d termination of ecl devices with ef emitter.

Each ic family has its own characteristics, limitations and advantages. Today the most widely used is something called cmos, complementary metal oxide semiconductor. Instead, it has a small voltage swing, less than a volt, and it internally switches current between two possible paths, depending on the output state. Logic families discussed in the chapter include transistor transistor logic ttl, metal oxide semiconductor mos logic, emitter coupled logic ecl. In this article, you will find the study notes on logic families which will cover the topics such as ecl, mos inverter, nand and nor with nmos, cmos, nand and nor with cmos, logic families comparison. Digital logic circuits are manufactured depending on the specific circuit technology or logic families.

The logic families which fall under the first kind are called bipolar families, this include diode logic dl, emitted coupled logic ecl, resistor transistor logic rtl, diode transistor logic dtl, transistor transistor logic ttl. Rtl, dtl, ttl, ecl to 7400 with its modern low voltage variants. This is a noror gate using emittercoupled logic, a highspeed type of logic using transistors. The quick reference attributes charts on page 3may be a good. The first ecl logic family was introduced by general electric in 1961. In computer engineering, a logic family may refer to one of two related concepts. If either one of them is high 700 mv, then the or output is high, and the nor output is low.

A circuit configuration or arrangement of the circuit elements in a special manner will result in a particular logic family. Others are more vendor specific flavors and may have unique electrical characteristics all. Difference between ttl cmos ecl ttl vs cmos vs ecl. The families included here comprise of emitted coupled logic ecl, resistor transistor logic rtl, diode transistor logic dtl, transistor logic ttl, and diode logic dl.

Lvds, cml, ecldifferential interfaces with odd voltages. Logic guide introduction and contents todays applications are evolving with greater functionality and smaller size. Directcoupled transistor logic dctl is similar to resistortransistor logic rtl but the input transistor bases are connected directly to the collector outputs without any base resistors. Emittercoupled logic ecl emittlercoupled logic ecl was invented in 1956 by hannon s. Saturation in ecl is avoided by using the bjt differential pair as a current switch.

Ecls major disadvantage is that each gate continuously draws current, which means that it requires and dissipates significantly more power than those of other logic families, especially when quiescent. For the love of physics walter lewin may 16, 2011 duration. Jan 16, 2020 dtl ttl ecl mos cmos pdf evolution of ttl family. Ttl transistortransistor logic families history and. In electronics, emittercoupled logic ecl is a highspeed integrated circuit bipolar transistor. Jan 16, 20 ecl is non saturated digital logic family. New technologies are continually being developed in an effort to improve the logic. Emitter coupled logic the main specialty of ecl is that it is operating in active region than the saturation region. The table also shows that the noise margin does not really get smaller as the voltage is reduced or as the logic family changes. These families vary by speed, power consumption, cost, voltage. The storage time is eliminated as the transistors are used in difference amplifier mode and are never driven into saturation. Ecls major disadvantage is that each gate continuously draws current, which means it requires and dissipates significantly more power than those of other logic families, especially when quiescent. Tis goal is to help designers easily find the ideal logic technology or function they need. Emittercoupled logic ecl based on bipolar transistors, but removes problems of storage time by preventing the transistors from saturating.

The basics of emittercoupled logic technical articles. Standard ttl 74 xxxll, low power ttl 74lxx low power schottky. Different gates are constructed using integrated circuits. The skew introduced by a logic device can be broken up into three areas. The first ecl logic family to be available in integrated circuits was introduced by motorola as mecl in 1962. In this article, you will find the study notes on logic families which will cover the topics such as integrated circuits, characteristics of digital circuits, logical families, digital ic terminology, dl, rtl, dtl and ttl. These families are extremely fast, offering propagation delays as short as 1 ns. Ecl s major disadvantage is that each gate continuously draws current, which means that it requires and dissipates significantly more power than those of other logic families, especially when quiescent. Emittercoupled logic ecl is the fastest logic circuit family available for. The first kind of logic families is bipolar families. Logic families significance and types of logic families.

This page compares ttl vs cmos vs ecl logic families and mentions difference between ttl and cmos and ecl based on various parameters such as fanout,power consumption,noise immunity etc. Digital logic families digital logic has evolved over the years and this process has led to the development of a variety of families of digital logic integrated circuits. This document describes the main logic families and their characteristics. Logic families are sets of chips that may implement different logical functions but use the same type of transistors and voltage levels for logical levels and for the power supplies.

As the current is steered between two legs of an emittercoupled pair, ecl is sometimes called. Current switching ecl is also vee sometimes called current. Ttl stands for transistor transistor logic, cmos stands for complementary metal oxide semiconductor and ecl stands for emitter coupled logic. Ecl uses an overdriven bjt differential amplifier with singleended input and limited emitter current to avoid the saturated fully on region of operation and its slow turnoff behavior. This page covers advantages and disadvantages of ecl. Is the fastest logic family and has the lowest propagation delay. Unlike the other logic families in this chapter, ecl does not produce a large voltage swing between the low and high levels. Each family has its own advantages and limitations. Many logic families were produced as individual components, each. The design of the digital ics takes place by making use of bipolar devices or mos or both. The pmos and i2l logic families were used for relatively short periods, mostly in special. For example, a certain amount of current is needed in order to operate correctly.

Logic families are offered at every priceperformance node along with benchmark delivery, reliability, and worldwide support. Firstly, the circuit inside the dotted box is a voltage reference circuit providing a reference voltage at the base of t2. One example is the philips norbits family of logic building blocks. In ecl technology a logic 0 is defined as having a larger negative voltage than a logic 1. Logic families and their characteristics website staff ui.

Integrated injection logic i2l the families rtl, dtl, and ecl were derived from the logic circuits used in early computers, originally implemented using discrete components. Ecl logic has the capability of significantly reducing the clock skew of a system over an equivalent design utilizing cmos or ttl technologies. The ecl basic circuits include the ornor gate, andnand gate, the reference voltage network, and ecl. As you can see in the figure, the emitters of the transistors q1 and q2 are coupled together. Emittercoupled logic ecl based on bipolar transistors, but removes problems of storage time by preventing the transistors from saturating very fast operation propagation delays of 1ns or less high power consumption, perhaps 60 mwgate low noise immunity of about 0. Logic families logic families are sets of chips that may implement different logical functions, but use the same type of transistors and voltage levels for logical levels and for the power supplies. Digital mos circuits can be classified into two categories. Within each logic family are one or more logic series that have distinctive characteristics, relative to other series within the same logic family. Emittercoupled logic ecl is a bjtbased logic family which is. Some are defined by industry standard committees, such as the tia, ieee, or jedec groups.

Ecl emittercoupled logic bjts operating in unsaturated mode i. Fill in the banks of the statements below concerning the following logic families. Therefore, gates are grouped into logic families such that all gates in a logic family obey the static discipline when used with other gates in the family. Emittercoupled spintransistor logic request pdf researchgate. Also note that the noise margin in cmos is higher than the noise margin in ttl for 5 volt logic. The digital ics are designed using any of either bipolar devices or mos or a combination of both. If you mix logic families the noise margin will need to be recalculated using the noise margin equation listed above. Mos metal oxide semiconductor field effect transistors. This meant that interoperation between ecl and other logic families, such as the popular ttl family, required additional interface circuits. The ecl family, ecl is also known as currentmode logic cml, was invented by ibm as current steering logic for use in the transistorized ibm 7030 stretch computer, where it was implemented using discrete components. For example, in the ttl logic family, there are several logic series. Lvds, cml, ecldifferential interfaces with odd voltages by john goldie, applications manager there are many differential signaling technologies available today. The recent invention of magnetoresistive bipolar spintransistors makes possible the creation of new spintronic logic families.

Jan 26, 2018 for the love of physics walter lewin may 16, 2011 duration. There have been many improvements in logical families such as ttl and cmos. Emitter coupled logic non saturated logic current mode logic. Logic done in emitter circuitry rather than collector. Logic selection guide how to use this guide the data on this page page 2give an historic overview of fairchilds available logic families. Typical propagation delays 1ns and below ecl noise margins are very low 150mv typ fanout is high 25 power dissipation remains. Paul shockman on semiconductor logic applications engineering contents of application note introduction. In ecl logic family, logic 0 is represented as about 1. A variant of ecl known as currentmode logic cml is utilized. Such a switch can be most conveniently realized using the differential pair.