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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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. Since the initial devices used oxide-isolated metal gates, they were called CMOS complementary metal—oxide—semiconductor logic. 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 dhl features of ytl family.

The diode-transistor logic, also termed as DTL, replaced RTL family because of greater fan-out capability and more noise margin. The positive supply terminal of the circuit is grounded while negative supply terminal is at negative 5. These cos only work with a 5V power supply. 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 drl met within the logic family.

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Logic family

Some such logic families use static techniques to minimize design complexity. Hence this family of logic gates is modified to transistor-transistor logic i. Retrieved from ” https: The PMOS and I 2 Rtl logic families were used for relatively short periods, mostly in special purpose custom large-scale integration circuits devices and are generally considered obsolete.

Analog, and Mixed-SignalMarcel Dekker, pp. Thus transistor s T1 and T2 are connected in differential amplifier configuration. Hence, output is connected to GND i. This was made by Texas Instruments as their “51XX” series. 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:. ECL logic family implements the efl in differential amplifier configuration in which transistors are never driven in the saturation region thereby improving the speed of circuit to a great extent.


This is done to minimize moss effect of noise introduced by the power supply and also to protect the gate from cmis that might occur accidently. RTL family is characterized by poor noise margin, poor fan-out capability, low speed and high power dissipation. Even for storage of device, all pins must be shorted.

Introduction year is when at least some of the devices of the family were available in volume for civilian uses. Many logic families were produced as individual components, each containing one or a few related basic logical functions, which could be used as “building-blocks” to create systems or as so-called “glue” to interconnect more complex integrated circuits.

However as these Ccmos developed, at first as SSI small scale integrated devices, with just a few transistors per chip, and then as MSI medium scale integrated devices with or more transistors, a problem arose that as more gates and therefore more transistors were packed into a single IC, the scale of integration would be limited jos the power dissipation of the device.

The working of this circuit is identical to that of DTL circuit. Caution for using MOS devices: The first diode—transistor logic family of integrated circuits was introduced by Signetics in Understand differences between logic families.

Difference between TTL ECL CMOS | TTL vs ECL vs CMOS

Transistor—transistor logic uses bipolar transistors to form its integrated circuits. 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. The integrated injection logic IIL or I 2 L uses bipolar transistors in a current-steering arrangement to implement logic functions. Learn about electronics Digital Electronics.

Diode logic was used with vacuum tubes in the earliest electronic computers in the s including ENIAC.

A typical 74 series IC is shown in Fig 3. RTL resistor-transistor logic and DTL diode-transistor logicsuccessfully used in early computers were superseded by TTL transistor-transistor logicwhich became the dominant technology. These design styles can typically be divided into two main categories, static techniques and clocked dynamic techniques.

Gates built with Schottky transistors use more power than normal TTL and switch faster.

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Logic family – Wikipedia

Archived from the original on dtp A large collector current of T1 is in such direction that it helps removing base charge of T2 and T3. Many motherboards have a voltage regulator module to provide the even lower power supply voltages required by many CPUs. Other such logic families, such as dl logicuse clocked dynamic techniques to minimize size, power consumption and delay. Toggle speed represents the fastest speed at which a J-K flip flop could operate.

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. From Wikipedia, the free encyclopedia.

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.

D1, D2 and D3. However, because the logic thresholds of CMOS were proportional to the power supply voltage, CMOS devices were well-adapted to battery-operated systems with simple power supplies. Several techniques and design styles are nos used in designing large single-chip application-specific integrated circuits ASIC and CPUs, rather than generic logic families cjos for use in moa applications. With HC and HCT logic and LS-TTL logic competing in the market it became clear that further improvements were needed to create the ideal logic device that combined high speed, with low power dissipation gtl compatibility with older logic families.

The logic level LOW is the voltage that drives corresponding transistor in cut-off region, while logic level HIGH drives it into saturation region.

However the laws of physics, as presently understood, say that this is not possible. These two logic families were not readily compatible; apart from the differences in supply voltage and speed, they were not particularly pin compatible, as illustrated in Fig. CMOS chips often work with a broader range of power supply voltages than other logic families. Thus, to interface this logic family with other, a translator circuit is needed which converts negative voltages to compatible positive dl levels.

The diode will conduct only when corresponding input is LOW. It has come to existence so as to overcome the speed limitations of DTL family.