Basic logic families pdf

It is a logic family consisting completely of transistors. In this tutorial, we will have a brief introduction to logic gates. Diode logic dl is the most primitive of all the digital logic families. 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. However, cmos power consumption increases faster with higher clock speeds than ttl does.

Electrical characteristics the characteristics of digital logic families are usually compared by analyzing the circuit of the basic gate in each family. Introduction to logic gates not, and, nand, or, nor. Digital electronics part i combinational and sequential. These quantities may be observed, measured, manipulated, and stored recorded. Ecl uses a differential amplifier as its basic circuit. Based on this, logic gates are named as and gate, or gate, not gate etc. The 74ls lowpower schottky family like the original uses ttl transistortransistor logic circuitry which is fast but requires more power than later families. Ppt logic families powerpoint presentation free to. These items are commonly available and can be obtained relatively inexpensively. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect. Also, in saying that logic is the science of reasoning, we do not mean. The logic families which fall under the first kind are called bipolar families, this include diode logic dl, emitted coupled logic ecl, resistor transistor logic rtl, diode transistor logic dtl, transistor transistor logic ttl. 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 gate is an electronic device which is used to compute a function on a two valued signal.

The processor accepts input data from various sensing devices, executes the stored user program, and sends appropriate output commands to. Basics of digital logic design computer science and. Difference between ttl cmos ecl ttl vs cmos vs ecl. Ccs created the lm page 8 to help guide community school efforts around improving student. The introduction of advanced lowpower schottky als further increased speed and reduced power consumption. Actually, there are many different ttl families, with a range of speed, power consumption, and other characteristics. A faster logic family called fast schottky f was also introduced that was faster than normal schottky ttl. Basic logic model program development logic model 14. However, this is not to suggest that logic is an empirical i. Ttl transistortransistor logic families history and. Transistortransistor logic topics the most commonly used bipolar logic family is transistortransistor logic. Designed so the desired circuit can be entered in relay ladder logic form. We will see the different logic levels in ttl circuits, cmos circuits, some simple logic gates like or, not, nand, and, etc. The main characteristics for some typical logic gates packages are shown in figures 9 and 10 next.

Consequently the output is solely a function of the current inputs. Signals, logic operations and gates rather than referring to voltage levels of signals, we shall consider signals that are logically 1 or 0 or asserted or deasserted. The two basic logic families are cmos complementary metal oxide. The circuit examples in this section are based on a representative ttl family, lowpower schottky ls or lsttl. In electronics, emittercoupled logic ecl is a highspeed integrated circuit bipolar transistor logic family. Cmos circuits do not draw as much power as ttl circuits while at rest. Logic family or series logic technology supply voltage volts basic details link. These inputs a and b are actually the input voltage applied to the base of a transistor or gate for mos transistor. Wh l i ttl nand i l h when at least one input to a ttl nand gate is low, the. Introduction to digital logic with laboratory exercises.

The concept was later refined by motorola and others to produce the still popular 10k and 100k ecl families. The basic circuit in the dtl logic is the nand gate. Integration levels gatetransistor ratio is roughly 110 ssi 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. Later, we will study circuits having a stored internal state, i. It first was available in 1962 and as the name implies it used just resistors and transistors. One basic function of ttl ic is as a complimenting switch or inverter. Which logic family has the highest power dissipation per gate a. What are the basic differences between cmos and ttl. The logic family refers to the general physical realization of a logical element, such as the ttl, emittercoupled logic ecl, or complementary metaloxide semiconductor cmos logic families. The digital ics are designed using any of either bipolar devices or mos or a combination of both. Digital ic gates are classified not only by their logic operation, but also by the specific logic circuit family to which it belongs. Logic families electronics sandeep kumar singh bca iind semester 2. The 74 series is often still called the ttl series even though the latest ics do not use ttl.

Dtl was first commercial available ic logic family in 5373 series. A quantity may be represented in analog and digital forms. Rather, logic is a nonempirical science like mathematics. Introduction to digital logic families classification of digital logic families. The first ecl logic family was introduced by general electric in 1961. Logic family 3 schottky ls, internal resistance values were increased to reduce power consumption and increase switching speed over the original version. Teaching and training guide february 2008 ellen taylorpowell, phd. The popularity of these ttl families stem from their ease of use, low cost, mediumto. It outlines its four big ideas, the five protective factors, pathways for improved outcomes, and implementation data. Logic gate circuits various logic families objective. There have been many improvements in logical families such as ttl and cmos. Winner of the standing ovation award for best powerpoint templates from presentations magazine.

For example, a certain amount of current is needed in order to operate correctly. In fact, it combines diodes and resistors so sometimes it is known as dioderesistor logic drl. Pdf on apr 20, 2017, shree krishna khadka published comparison of ic logic families find, read and cite all the research you need on researchgate. Gates are simplest digital logic circuits, and they implement basic logic operations functions. Healthy families new jersey logic model for program management. The output stage of most ttl logic is a totempole circuit. Healthy families new jersey logic model for program. Families or nested 27 logic models multiple logic models 33 multilevel system 34 multicomponent 35 5464 4 24. Logic gates are the basic building blocks of any digital system. Logic 1 and logic 0 are a bit more complex that 5v and 0v because these digital ics are really little analogue circuits posing as digital.

Strengthening families 101 center for the study of. We will also consider ways to determine whether certain statements are true or false methods of proof. Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. Overview integration, moores law early families dl, rtl ttl evolution of ttl family ecl cmos family and its evolution overview 2.

This page compares ttl vs cmos vs ecl logic families and mentions difference between ttl and cmos and ecl based on various parameters such as fanout,power consumption,noise immunity etc. Ttl stands for transistor transistor logic, cmos stands for complementary metal oxide semiconductor and ecl stands for emitter coupled logic. As the current is steered between two legs of an emittercoupled pair, ecl is sometimes called. Digital logic families phys3360aep3630 lecture 26 these also have lower power requirements than the standard ttl these also have lower power requirements than the standard ttl these also have lower power requirements than the standard ttl these also have lower power requirements than the standard ttl overview integration, moores law early families dl, rtl t. Transistor transistor logic ttl family one basic function of ttl ic is as a complimenting switch or inverter. These results should be developed around a logic model lm.

Ecl uses an overdriven bjt differential amplifier with singleended input and limited emitter current to avoid the saturated fully on region of operation and its slow turnoff behavior. Introduction to and classification of digital logic. As well as the basic logic functions, compatible ics are available, which contain particular useful combinations of gates providing a convenient way of constructing more complex circuits. Commercially it starts with the 74 series like the 7404, 74s86 etc. These logic gates perform the basic boolean functions, such as and, or, nand, nor, inversion, exclusiveor, exclusivenor. Simple digital logic gates can be made by combining transistors, diodes and resistors. Each logic family has its own basic electronic circuit upon which more complex digital circuits and functions are developed. The relationship between the input and the output is based on a certain logic. Digital logic states all digital electronic circuits and microprocessor based systems contain hardware. Each ic family has its own characteristics, limitations and advantages. To understand basic gate operation of following logic families. It is extremely simple and inexpensive because it only uses passive components. The basic logic gates are the basic building blocks of more complex logic circuits. Introduction to programmable logic controllers plcs.

It was build in 1961 by james l bui and commercially used in logic design in 1963. Logic families significance and types of logic families. Within each logic family are one or more logic series that have distinctive characteristics, relative to other series within the same logic family. There are different families of logic gates in digital logic design. Electronics club 74 series logic ics families, 74hc. Special versions of the basic logic gates are also explained. The ttl family the input of a ttl logic gate is characterized by a multi emitter transistor. In this module, the differences and similarities between the various families of logic ics available are described, along with their important operating conditions. Many logic families were produced as individual components, each containing one or a few related basic. The 74hc family has highspeed cmos circuitry, combining the speed of ttl with the very low power consumption of the 4000 series. A two input gate will have two emitters and a four input gate will have four emitters.

This powerpoint is an extensive introduction to strengthening families. Logic families can be classified broadly according to the technologies they. It has evolved from the original golddoped saturated 7400 logic, to schottkyclamped logic, and finally to the modern advanced families of ttl logic. Voltage levels range from 0 to vcc where vcc is typically 4. The pair is biased with a constantcurrent source i, and one side is connected to a reference voltage v r. The newest ecl family, eclinps literally, ecl in picoseconds, offers maximum. Such a switch can be most conveniently realized using the differential pair shown in fig. These families are extremely fast, offering propagation delays as short as 1 ns.