One of the most popular and widely used types of logic gates made of transistors is called the emitter coupled logic or ecl. The single stage common emitter amplifier circuit shown above uses what is commonly called voltage divider biasing. Circuit architecture emitter coupled logic ecl is a nonsaturating form of digital bipolar circuit architecture. Emitter follower and darlington amplifier are the most common examples for feedback amplifiers. Usually, these circuits or gates, as they are commonly known, have multiple. The base region is dimensionally thin compared to the emitter and collector regions. Supplementary material to accompany digital design. Such a switch can be most conveniently realized using the differential pair shown in fig. Eclinps emitter coupled logic in pico seconds acronymfinder. Emittercoupled logic ecl is a bjtbased logic family which is generally considered as the fastest logic available. Pier letters online design of radiated comb generator using.
Emittercoupled logic is based on the use of the currentsteering. Transistortransistor logic ttl complementary metaloxide semiconductor logic cmos ngntikmaos nchannel and pmos pchannel and using them in a complementary fashion emitter coupled logic ecl. Bipolar junction transistors bjt and its applications. 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. Eclinps stands for emitter coupled logic in pico seconds. Emitter follower circuit has a prominent place in feedback amplifiers. It makes use of a transistorbased differential amplifier to amplify and combine digital signals. Emittercoupled logic ecl basic ecl inverternoninverter ecl current switch basic ecl inverternoninverter vtc v oh v cc according to inverting output. More speedy small voltage swing fastest switching constant current supply noise immunity 5.
The base lead connects to the center semiconductor material of this three layer device. Contains the most extensive coverage of digital integrated circuits available in a single source. Ttl evolution schottky series 74ls00 ttl a major slowdown factor in bjts is due to transistors going inout of saturation shottky diode has a lower forward bias 0. The improved characteristics of this logic family are derived from exploiting the magnetic properties of the spintransistors. The same techniques, however, can be applied to other types of ecl. One of the most popular and widely used types of logic gates made of transistors is called the emittercoupled logic or ecl. 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. Emitter coupled logic circuits an overview sciencedirect topics. In addition to providing the input stage of the operational amplifier, this configuration is the foundation for emitter coupled logic ecl, a very high speed, universally employed family of logic circuits. Usually, these circuits or gates, as they are commonly known. When used as a switch, the left basegrid is used as signal input and the right basegrid is grounded.
Ecl emitter coupled logic a digital circuit composed of bipolar transistors in which the emitter ends are wired together. This is a noror gate using emittercoupled logic, a highspeed type of logic using transistors. The pair is biased with a constantcurrent source i, and one side is connected to a reference voltage v r. Finally found an answer and a citation from 1975, with the introduction of the kl10, until 1991, when nvax was released, the highest performance processors at dec were built with ecl emitter coupled logic technology. Ecl emitter coupled logic, pdf file ecl backplane design ecl outputs are perfectly suited to drive transmission lines. Pecl, or positive emitter coupled logic, is nothing more than standard ecl. Emittercoupled logic ecl objective questions digital electronics objective questions. I hope the given information in the article is helpful to give some good information and understanding the project. In a collector coupled symmetrical astable multivibrator if it is desired to vary the frequency.
Ecl gates to attain a fault coverage of around 98%, both logical and nm fault testing have to be used. Transistor emitter follower, common collector amplifier. Dont expect much boom from this little circuit, the main purpose of this circuit is preamplification i. The simplest way of connecting an emitter follower is to directly couple the input as shown below. The first ecl logic family was introduced by general electric in 1961. Ecl is considered to be a very highspeed logic family. Ecl achieves its highspeed operation by employing a relatively small voltage swing and preventing the transistors from entering the saturation region. Emitter follower is a case of negative current feedback circuit. High speed paths are typically implemented within deep submicron cmos integrated circuits. Emitter follower input resistance dc coupled emitter follower, common collector circuit. 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.
These are the mostly used ones with a number of applications. Eclinps is defined as emitter coupled logic in pico seconds very rarely. Fiber reinforcements and general theory of composites. In computer engineering, a logic family may refer to one of two related concepts. Emittercoupled logic article about emittercoupled logic. As a result, none of the transistors in the gate ever enter saturation, nor do they ever get turned completely off. Emitter coupled logic article about emitter coupled logic. This type of biasing arrangement uses two resistors as a potential divider network across the supply with their center point supplying the required base bias voltage to the transistor. Emitter coupled logic is based on the use of a multiinput differential amplifier to amplify and combine the digital signals, and emitter followers to adjust the dc voltage levels. A technology for building logic gates where the emitter of a transistor is used as the output rather than its collector. The basics of emittercoupled logic technical articles. In electronics, emittercoupled logic ecl is a highspeed integrated circuit bipolar transistor logic family. Emittercoupled logic wikimili, the free encyclopedia. A standard emitter coupled logic ecl output driver typically uses a current switching differential with an emitter follower for level shifting the output and the internal cml levels to familiar ecl levels.
It gives students, researchers, and practicing engineers the necessary design and modelling tools for validating electronic design concepts involving bipolar junction transistors. Emittercoupled logic how is emittercoupled logic abbreviated. The circuit families described in detail are transistortransistor logic ttl, sttl, and asttl, emittercoupled logic ecl, nmos logic, cmos logic, dynamic cmos, bicmos. Request pdf emittercoupled spintransistor logic the recent invention of. Pdf use emitter coupled logic in your rf applications.
The input resistance can easily be calculated for a circuit because it is. It is used for calibration and self checking of the test systems. The common emitter rc coupled amplifier is one of the simplest and elementary transistor amplifier that can be made. And8020d termination of ecl devices with ef emitter. Interfacing between lvpecl, vml, cml and lvds levels. Cml is a malignant myeloproliferative disorder of hematopoietic stem cells that affects 12 people per 100,000 annually and is reported to account for 1520% of adult leukemia cases. Comb generator has been an indispensable tool in the electromagnetic compatibility emc testing field. Emitter coupled logic is based on the use of the currentsteering switch introduced in section 15. We have constructed emittercoupled spintransistor logic circuits by routing the ecl differential amplifier currents to create magnetic fields that control the state of spintransistors. In electronics, emittercoupled logic ecl is a highspeed integrated circuit bipolar transistor. Emittercoupled spintransistor logic request pdf researchgate. Unlike the other logic families in this chapter, ecl does not produce a large voltage swing between the low and high levels.
By placing the wire from the output stage of ecl logic elements near. This document focuses on these four logic levels, because they are now the most prevalent in todays communications systems. Basic ecl inverternoninverter ecl current switch emitter. Ecl gates switch faster than ttl gates, but consume more power. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. When multiple digital signals have to be combined, engineers use several types of logic gates. Astable multivibrator collector coupled, emitter coupled. May 26, 2015 when multiple digital signals have to be combined, engineers use several types of logic gates.
Ecl uses an overdriven bjt differential amplifier with singleended input and limited emitter current to avoid the saturated fully on region of. This article gives information about what is a bipolar junction transistor, types of bjt, advantages, applications, and characteristics of the bipolar junction transistors. Fast, hot, and not very dense, ecl was the technology of choice for highend systems, not just at dec, but at computer. To give concreteness to our study of ecl, in the following we shall consider the popular ecl 10k in some detail. Figure c shows the circuit diagram of an emitter coupled asable multivibrator. In addition to providing the input stage of the operational amplifier, this configuration is the foundation for emittercoupled logic ecl, a very high speed, universally employed family of logic circuits. Termination of ecl devices with ef emitter follower output structure. Topics covered circuit construction logical operation of ecl ornor circuit. Ecl design principles chapter 3 ecl design principles this chapter is an introduction to general and synergyspeci. A standard emitter coupled logic ecl output driver typically uses a current switching differential with an emitter.
Emitter coupled logic circuits cml is a malignant myeloproliferative disorder of hematopoietic stem cells that affects 12 people per 100,000 annually and is reported to account for 1520% of adult leukemia cases. Paul lee logic applications engineer on semiconductor introduction recent growth in high. A differential amplifier is used as the input stage emitter coupled logic gates and as switch. Emittercoupled logic ecl3 supplementary material to accompany digital design principles and practices, fourth edition, by john f. Technology of digital components, ttl logic families, ttl.
It provides a foundation for the next two chapters. Transistortransistor logic ttl complementary metaloxide semiconductor logic cmos ngntikmaos nchannel and pmos pchannel and using them in a complementary fashion emitter coupled logic ecl integrated circuits. How is emitter coupled logic in pico seconds abbreviated. Sep 20, 2019 in electronics, emitter coupled logic ecl is a highspeed integrated circuit bipolar transistor logic family.
Ecl emittercoupled logic a digital circuit composed of bipolar transistors in which the emitter ends are wired together. Emitter base collector npn symbol emitter base collector pnp symbol construction simplified diagram the bipolar transistor is a three layer semiconductor. Design of radiated comb generator using singleended positive emitter coupled logic pecl d flipflop by yoppy and m. Digital logic circuits devices which can be used to design digital circuits. We have constructed emitter coupled spintransistor logic circuits by routing the ecl differential amplifier currents to create magnetic fields that control the state of spintransistors. Ecl circuits are fast 1 ns delays typical because they avoid saturation. All voltage are negative more negative logic low less negativelogic high. Introduction to emitter coupled logic ecl family youtube.
Emittercoupled logic is based on the use of the currentsteering switch introduced in section 15. If either one of them is high 700 mv, then the or output is high, and the nor output is low. Emittercoupled logic ecl is the fastest logic circuit family available for conventional. Here, we report a theoretical investigation of the vdw magnetic tunnel. In electronics, emitter coupled logic ecl is a highspeed integrated circuit bipolar transistor logic family. Electronic circuits with matlab, pspice, and smith chart wiley. It achieves its highspeed operation by employing a relatively small voltage swing and. Emittercoupled logic is based on the use of a multiinput differential amplifier to amplify and combine the digital signals, and emitter followers to adjust the dc voltage levels.
1245 718 674 547 782 243 867 843 508 920 829 380 420 26 689 129 1129 810 1393 266 1230 482 1458 1496 560 1477 932 1530 119 457 1113 580 575 1197 935 114 385 919 516 371 742 74 1170