Dtl logic family pdf file

The input is connected through a pair of diodes in series with the base of the transistor. In dtl diode transistor logic, all the logic is implemented using diodes and transistors. The popularity of these ttl families stem from their ease of use, low cost, mediumtohigh speed operation, and good output drive capability. Early transistorized computers were implemented using discrete transistors, resistors, diodes and capacitors. Logic family 3 schottky ls, internal resistance values were increased to reduce power consumption and increase switching speed over the original version. Emitter coupled logic ecl or current mode logic cml 6. Although nowadays they have been replaced in many applications by bigger, faster smarter chips, the 74 series families continue to play an important role in electronics, and learning about them is a sound basis for. Fill in the banks of the statements below concerning the following logic families.

Ttl stands for transistor transistor logic, cmos stands for complementary metal oxide semiconductor and ecl stands for emitter coupled logic. The diode connected directly to the transistor base serves to raise the input. The most commonly used bipolar logic family is transistortransistor logic. Dtl was first commercial available ic logic family in 5373 series.

The circuit examples in this section are based on a representative ttl family, lowpower schottky ls or lsttl. The he4000b logic family specification datasheet, cross reference. The 74 series of logic ics introduced in this module, has been the backbone of digital electronics for about the last 50 years. Chapter 5 diode transistor logic university of babylon. Diodetransistor logic dtl was used in the ibm 608 which was the first alltransistorized computer.

Technology of digital components, ttl logic families, ttl. Introduction 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 logic family may also refer to a set of techniques. Cmos logic families many families of logic exist beyond static cmos comparison of logic families for a 2input multiplexer briefly overview pseudonmos differential cvsl dynamicdomino complementary passgate. Diode logic is used extensively but not in integrated circuits. Characteristics of digital ics digital logic families tech gurukul by dinesh arya check out my amazon store link f. The bipolar families of logic circuits use the bipolar transistors fabricated on the chip. There have been many improvements in logical families such as ttl and cmos.

Digital logic has evolved over the years and this process has led to the development of a variety of families of digital logic integrated circuits. The transistortransistorlogic ttl family was developed in the use of transistor switches for logical operations and defines the binary values as. A logic family is a collection of different integratedcircuit chips that have similar input, output, and internal circuit characteristics, but they perform different logic functions and, or, not, etc. The ic04 locmos he4000b logic family specifications hef, hec pdf 2 download hef package outlinesinfo. If input x, y or z is low, the corresponding diode conducts current, through the 4. Transistor logic and then transistortransistor logic, dtl and ttl. Hef schmitttrigger in the he4000b logic family specification family specifications hef, hec he4000b hef40240b hef40240bd hef40240bt. Pdf diode transistor logic diode logic suffers from voltage degradation from one stage to the next. Transistortransistorlogic topics digital design principles ttl. Logic families logic families are sets of chips that may implement different logical functions, but use the same type of transistors and voltage levels for logical levels and for the power supplies. Diodetransistor logic dtl essentially diode logic with transistor amplification. Diodetransistor logic dtl is a class of digital circuits that is the direct ancestor of transistortransistor logic. Within each family, several subfamilies of logic types are. It suffers from low speed, especially in comparison to ttl.

In the bipolar category there are three basic families called, diode transistor logic dtl, transistor transistor logic ttl and emitter coupled logic ecl. Hundreds of different, but directly interconnectable logic ics are available. Dr l is a basic logic family and, as a group of circuits, plays little part in logic. Resistortransistor logic rtl diodetransistor logic dtl emitter coupled logic ecl logic families can be classified broadly according to the technologies they are built with transistortransistor logic ttl cmos logic ttl and cmos logic family is most widely used ic technologies. They deliver speed and drive on a par with ttl, quashing worries about highspeed systems built. Transistortransistorlogic topics the most commonly used bipolar logic family is transistortransistor logic. It has come to existence so as to overcome the speed limitations of dtl family. Ttl input or output lead is defined to be positive if the. The diodetransistor logic, also termed as dtl, replaced rtl family because of greater fanout capability and more noise margin.

The pmos and i 2 l logic families were used for relatively short periods, mostly in special purpose custom largescale integration. Recommended software programs are sorted by os platform windows, macos, linux, ios, android etc. It indicates high and low logic states by means of leds, giving visual indication only if the voltage levels are appropriate for each state. Ttl transistortransistor logic families history and. Dtl inverter circuit theory the dtl inverter uses a transistor and a collector load resistor as shown in the circuit diagram. Actually, there are many different ttl families, with a range of speed, power consumption, and other characteristics.

Each family has its own advantages and limitations. Because of this diodetransistor logic dtl rapidly replaced rtl in most digital applications. Dtl offers better noise margins and greater fanouts than rtl, but suffers from low speed, especially in comparison to ttl. The basic circuit in the dtl logic is the nand gate. Here is a schematic diagram for a logic probe built using comparators. The above two figures show the actual circuit diagram of a circuit where the output of a single nand gate which belongs to a standard ttl transistor transistor logic logic family feeds the inputs of various nand gate which belongs to the same logic family the first figure is for the state when the logic is high and the second figure is during the logic low state. Logic families electronics sandeep kumar singh bca iind semester 2. That means all the gates belonging to the bipolar family use the transistorised circuits. It is a logic family consisting completely of transistors.

The following logic families are the most frequently used. A logic probe is a very useful tool for working with digital logic circuits. It was build in 1961 by james l bui and commercially used in logic design in 1963. A family of simple resistortransistor logic integrated circuits was developed at fairchild semiconductor for the apollo guidance computer in the diodetransistor logic, also termed as dtl, replaced rtl family because of greater fanout capability and more noise margin. A faster logic family called fast schottky f was also introduced that was faster than normal schottky ttl.

Which of the following is the fastest logic family a. That model simply specifies all the activities, all the risk and protective factors and all the behaviors designed to affect the two health goals of draw the linerespect the line. Rtl was superceded in the 1960s by diodetransistor logic and then transistortransistor logic, dtl and ttl respectively. Ttl transistortransistor logic ecl emittercoupled logic mos metaloxide semiconductor cmos complementary metaloxide semiconductor. Diodetransistor logic dtl diodetransistor logic, or dtl, refers to the technology for designing and fabricating digital circuits wherein logic gates employ both diodes and transistors. Rtl, dtl, ttl and cmos family for nand logic and nor logic. By letting diodes perform the logical and or or function and then amplifying the result with a transistor, we can avoid some of the limitations of rtl. It is called so because the logic gating function e. Each logic family has its own basic electronic circuit upon which more complex digital circuits and functions are developed. Logic families are sets of chips that may implement different logical functions. The output waveform shown in fig 8 is of cmos nand logic and in fig 9 is cmos nor logic.

In the figures below, first is a snapshot of a logic model for draw the linerespect the line. Logic families significance and types of logic families. Number of logic gates at the next stages that can be loaded to a given logic gate output is the fanout. Many logic families were produced as individual components, each containing one or a few related basic logical functions, which could be used as buildingblocks to create systems or as socalled glue to. Fanout must be examined for both possible output states.

One example is the philips norbit family of logic building blocks. Logic families can be classified broadly according to the. The families rtl, dtl, and ecl were derived from the logic circuits used in early computers, originally implemented using discrete components. 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. Rtl resistortransistor logic and dtl diodetransistor logic, successfully used in early. Zion fanout the fanout of a logic gate is the number of inputs that the gate can drive without exceeding its worstcase loading specifications. Commercially it starts with the 74 series like the 7404, 74s86 etc. Which of the following logic has the fan out of more than 50 a. The term transistortransistor is because both logic function and amplification is done by transis. Dtl was initially made with discrete transistors and resistors before being integrated onto silicon.

Evaluation of logic families using nor and nand logic gates. Each ic family has its own characteristics, limitations and advantages. The most widely used bipolar technology for digital ics is a. A basic circuit in the dtl logic family is as shown in the figure below. Among the technologies discussed here are dl, rtl, dtl, ecl, ttl. Diode logic pdf complete license key only permits the or and. Digital logic gates nand and nor are called universal logic gate because. These families vary by speed, power consumption, cost, voltage. Low power schottky lsttl was the industry standard logic family for many years. Click on the tab below to simply browse between the.