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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Transistors T3 and T4 are emitter-followers used for DC level-shifting of output voltages. Ideally logic gates should be able coms change state immediately and consume little or no power.
This causes density to be reduced and complex fabrication process. For example, early digital clocks or electronic calculators may have used one or more PMOS devices to provide most of the logic for the finished product. Thus, voltage Vcc appears at output I. D1, D2 and D3. The PMOS and I 2 L logic families were used for relatively short periods, mostly in special purpose custom large-scale integration circuits devices and are generally considered obsolete.
DTL was also made by Fairchild and Westinghouse. It must connected to ground or supply.
Views Read Edit View history. Before the widespread use of integrated circuits, various solid-state and vacuum-tube logic systems were used but these were never as standardized and interoperable as the integrated-circuit devices.
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.
Several early transistorized computers e. The list of packaged building-block logic families can be divided into categories, listed here in roughly chronological order of introduction, along with their usual abbreviations:. This was made by Texas Instruments as their “51XX” series.
CMOS Complimentary Metal Oxide Semiconductor chips, designed for minimum power, got faster and TTL families, using bipolar transistors for optimum speed, were cmls that cmo only increased speed but also reduced power consumption. For the same cmks 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.
Introduction year is when at least some of the devices of the family were available in volume for civilian uses. Retrieved from ” https: Hons All rights reserved.
Due to these undesirable characteristics, this family is now obsolete. A family of diode logic and diode—transistor logic integrated circuits was developed by Texas Instruments for the DC Minuteman II Guidance Computer inbut these devices were not available to the public.
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. Hence, output is connected to GND i. As well as the basic logic dyl, compatible ICs are available, which contain particular useful combinations el gates providing a convenient way of constructing more complex circuits.
The logic gates introduced in Module 2. Understand differences between logic families.
Not shown are some early obscure logic families from the early s such as DCTL direct-coupled transistor logicwhich did not become widely available. Variations on the basic TTL design are intended to reduce these effects and improve speed, power consumption, or both. The increase in portable battery dl 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.
The integrated injection logic IIL or I 2 L uses bipolar transistors in a current-steering arrangement to implement logic functions.
Although each gate only dissipates a few milliWatts, the heat generated within a single large-scale integrated LSI circuit containing tens of thousands of transistors could potentially quickly destroy the IC.
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,os However the laws of physics, as presently understood, say that this is not possible. The positive supply terminal of the circuit is grounded while negative supply terminal is at negative 5. All electrical circuits must consume some power, and any change in the voltages and currents in that circuit must take at least some time. Motorola Semiconductor Products Inc.
Logic Families – Power, Speed and Compatibility
The codes used vary between manufacturers, but package details are usually included on the IC datasheet. ICs of different families can sometimes also be directly connected together, but may require some extra circuitry at the interface of the two IC families to maintain compatibility.
If any of input elc MOS is left unconnected, the open input terminal which has very high input impedance may take any stray electric charge as input and can develop extreme dangerous high voltage which can damage the device and may also harm the person handling the device.
Here, p-channel devices are in series and n-channel devices are in parallel. A short list of the most important family designators of these newer devices includes:.
Wikipedia articles needing clarification from July