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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It must connected to ground or supply. However the laws of physics, as presently understood, say that this is not possible.

Logic Families – Digital Electronics

If both the inputs are LOW, then both the transistors are in cut-off i. CMOS chips often work with a broader range of power supply voltages than other logic families. If any of input of 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.

Some such logic families use static techniques to minimize design complexity.

A typical 74 series IC is shown in Fig 3. Learn about electronics Digital Electronics. See static versus dynamic logic for some discussion on the advantages and disadvantages of each category.

It has come to fmos so as to overcome the speed limitations of DTL family.

Difference between TTL ECL CMOS | TTL vs ECL vs CMOS

It could be used both with logic devices which used 3. Values are very typical and would vary slightly depending on application conditions, manufacturer, temperature, and particular type of logic circuit. Here, p-channel devices are in series and moz devices are in parallel. D1, D2 and D3. The diodes D1, D2 and D3 are replaced by emitter-base junctions of a multiple-emitter transistor labeled T1.


These design styles can typically be divided into two main categories, static techniques and clocked dynamic techniques. The increase in portable battery powered electronic devices along with the ability of chip manufacturers to make the component parts of ICs much smaller also meant that power could ecll reduced and speed increased.

Making direct connections between ICs of a single family or sub family is usually very simple.

Powered by Create your own unique website with customizable templates. Chip designers therefore had to try and reconcile the fact that higher speeds meant more power consumption, and so some families developed, using optimum speed whilst others were developed to use the minimum of power. The collector-base junction of T1 is back-biased and T1 operates in normal active region. Analog, and Mixed-SignalMarcel Dekker, pp. Motorola Semiconductor Products Inc.

This made CMOS devices ideal for battery operation. Texas Instruments introduced the series TTL family in The German physicist Walter H. RTL family is characterized by poor noise margin, poor fan-out capability, low speed and high power dissipation. From Wikipedia, the free encyclopedia.

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. Due to number of diodes used in this circuit, the speed of the circuit is significantly low. Schottky formulated a theory predicting the Schottky effectwhich led to the Schottky diode and later Schottky transistors.

Views Read Edit View history. RTL resistor-transistor logic and DTL diode-transistor logicsuccessfully used in early computers were superseded by TTL transistor-transistor logicwhich became the dominant technology. Because CMOS and TTL families can now operate at similar speeds and similar power consumption, the 74HCT a CMOS sub-family compatible with TTL pinouts and voltage levels now makes it possible to easily interface both families within in a single design, so enabling the use of the best features of each family.

CMOS gates can also tolerate much wider voltage ranges than TTL gates because the logic thresholds are approximately proportional to power supply voltage, and not the fixed levels required by bipolar circuits. The extremely small capacitance of the on-chip wiring caused an increase in performance by several orders of magnitude. Even for storage of device, all pins must be shorted.


If any of the diode is conducting i. These are generally used “on-chip” and are not delivered as building-block medium-scale or small-scale integrated circuits. As the overall performance of these families increased they also became more compatible. Thus, none of the un-used inputs of MOS device should be left unconnected. Early transistorized computers were implemented using discrete transistors, resistors, diodes and capacitors.

Several early transistorized computers e. Static Dynamic Domino logic Four-phase logic. The first diode—transistor logic family of integrated circuits was introduced by Signetics in The following logic families would either have been used to build up systems from functional blocks such as flip-flops, counters, and gates, or else would be used as “glue” logic to interconnect very-large scale integration devices such as memory and processors.

Module 3.1

The positive supply terminal of the circuit is grounded while negative supply terminal is at negative 5. Since the transistors of a standard TTL gate are saturated switches, minority carrier storage time in each junction limits the switching speed of the device. Thus transistor s T1 and T2 are connected in differential amplifier configuration. 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.

Logic family

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 ms levels and power supply characteristics within a family.

This means that the current draw of CMOS devices increases with switching rate controlled by clock speed, typically. Understand differences between logic families.