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In electronics, emitter coupled logic, or ECL, is a logic family in which current is steered through bipolar transistors to compute logical functions. ECL is sometimes called 'current mode logic'. In computer engineering, 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. ...
A bipolar junction transistor (BJT) is a type of transistor. ...
Logic, from Classical Greek λόγος logos (the word), is the study of the principles and criteria of valid inference and demonstration. ...
The chief characteristic of ECL is that the transistors are always in the active region and can thus change state very rapidly, allowing ECL circuits to operate at very high speed. Its major disadvantage is that the transistors are continuously drawing current, which means the circuits require a lot of power. Most of this power is wasted as heat. A bipolar junction transistor (BJT) is a type of transistor. ...
There are many kinds of circuit An electric circuit interconnects electrical elements or electronic elements together usually to perform some useful function. ...
Explanation TTL and related families use transistors as digital switches where transistors are either cut off or saturated, depending on the state of the circuit. ECL gates use differential amplifier configurations at the input stage. A bias configuration supplies a constant voltage at the midrange of the low and high logic levels to the differential amplifier, so that the appropriate logical function of the input voltages will control the amplifier and the base of the output transistor (this output transistor is used in common collector configuration). The propagation time for this arrangement can be less than a nanosecond, making it the fastest logic family through several years. A Motorola 68000-based computer with various TTL chips. ...
A digital system is one that uses discrete values (often electrical voltages), especially those representable as binary numbers, or non-numeric symbols such as letters or icons, for input, processing, transmission, storage, or display, rather than a continuous spectrum of values (ie, as in an analog system). ...
Electrical switches. ...
A bipolar junction transistor (BJT) is a type of transistor. ...
Simple form of a differential amplifier A differential amplifier is a type of an electronic amplifier that multiplies the difference between two inputs by some constant factor (the differential gain). ...
This article or section does not adequately cite its references or sources. ...
International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ...
Simple form of a differential amplifier A differential amplifier is a type of an electronic amplifier that multiplies the difference between two inputs by some constant factor (the differential gain). ...
Typical common collector or emitter follower circuit. ...
In computer science, the propogation delay is the amount of time starting from when the input to a logic gate becomes stable and valid to the time that the output of that logic gate is stable and valid. ...
Characteristics Other noteworthy characteristics of the ECL family include the fact that the large current requirement is approximately constant, and does not depend significantly on the state of the circuit. This means that ECL circuits generate relatively little power noise, unlike many other logic types which typically draw far more current when switching than quiescent, for which power noise can become problematic. In an ALU - where a lot of switching occurs - ECL can draw lower mean current than CMOS. The arithmetic logic unit/arithmetic-logic unit (ALU) of a computers CPU is a part of the execution unit, a core component of all CPUs. ...
Power supplies and logic levels The ECL circuits available on the open market usually operated with negative power supplies (-5.2 volts), and logic levels incompatible with other families. This meant that interoperation between ECL and other logic families, such as the popular TTL family, required additional interface circuits. The fact that the high and low logic levels are relatively close meant that ECL suffers from small noise margins, which can be troublesome. A Motorola 68000-based computer with various TTL chips. ...
At least one manufacturer, IBM, made ECL circuits for use in the manufacturer's own products; the power supplies were substantially different from those used in the open market.[1] International Business Machines Corporation (known as IBM or Big Blue; NYSE: IBM) is a multinational computer technology and consulting corporation headquartered in Armonk, New York, USA. The company is one of the few information technology companies with a continuous history dating back to the 19th century. ...
Usage The drawbacks associated with ECL have meant that it has been used mainly when high performance is a vital requirement. Other families (particularly advanced CMOS variants) have replaced ECL in many applications, even mainframe computers. However, some experts predict increasing use of ECL in the future, particularly in conjunction with more widespread adoption of advanced semiconductors such as GaAs, which has always been seen as the semiconductor of the future, but cannot be produced as cheap/clean as Si and is toxic. Static CMOS Inverter Complementary metal–oxide–semiconductor (CMOS) (see-moss, IPA: ), is a major class of integrated circuits. ...
This article is about the chemical compound. ...
It has been suggested that Silicons ranking be merged into this article or section. ...
Older high-end mainframe computers, such as the Enterprise System/9000 members of IBM's ESA/390 computer family, used ECL;[1] current IBM mainframes use CMOS. IBM logo IBM ESA/390 (Enterprise Systems Architecture/390) has been introduced in the 1990s and is IBMs last 31-bit-address/32-bit-data mainframe computing design, copied by Amdahl, Hitachi, and Fujitsu among other competitors. ...
The equivalent of emitter coupled logic made out of FETs is called source coupled FET logic (SCFL). The field-effect transistor (FET) is a transistor that relies on an electric field to control the shape of the nonconductive depletion layer within a semiconductor material, thus controlling the conductivity of a channel in that material. ...
References - ^ a b A. E. Barish et al. (1992). "Improved performance of IBM Enterprise System/9000 bipolar logic chips". IBM J. of Research and Development 36 (5): 829–834.
See also Resistor-transistor logic (RTL) is a class of digital circuits built from bipolar junction transistors (BJT), and resistors; it is the earliest transistorized digital logic used. ...
Diode-Transistor Logic (DTL) Diode-Transistor Logic, or DTL, refers to the technology for designing and fabricating digital circuits wherein logic gates employ both diodes and transistors. ...
A Motorola 68000-based computer with various TTL chips. ...
Static CMOS Inverter Complementary metal–oxide–semiconductor (CMOS) (see-moss, IPA: ), is a major class of integrated circuits. ...
Positive Emitter Coupled Logic, or PECL, is a further development of the emitter coupled logic (ECL) technology and requires a positive 5V supply instead of a negative -5V supply. ...
Low Voltage Positive Emitter Coupled Logic, or LVPECL, is a further development of the emitter coupled logic (ECL) technology and requires a positive 3. ...
Integrated Injection Logic (IIL, I2L, or I2L) is a class of digital circuits built with multiple collector bipolar junction transistors (BJT). ...
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