At any given moment, every terminal is in one of the two binary conditions false high or true low. Design of basic logic gates using nor gate not, or and and. The circuit would have two ntype transistors in parallel in the pullup network, and two ptype transistors in series for the pulldown network. Sep 07, 2015 the word nor gate is just an short form of the not and or gate combination. Mathematics, portland state university 1997 minor b. Logic gates a b out 0 0 0 0 1 1 1 0 1 1 1 1 a b out. Construction and working mechanism of xnor gate xnor gate using bjt and diodes. Single bit full adder design using 8 transistors with novel 3 transistors xnor gate manoj kumar 1, sandeep k. A general method in synthesis of pass transistor circuits. Logic gates are basically are group of three basic logic gates specifically called as not, and and or gate. So we need not, and and or gates to form an xor circuit. Using five 2 input nand gate as shown in figure below we may realize 4 input nand gate.
What exactly does a 10transistor xor gate look like. Physical realization of a 4terminal mosfets tunomyo lsa gate is intersection of active, poly, and nselect. Lowpower and fast full adder by exploring new xor and xnor gates. The first solution is to add a feedback between the xor and xnorgate and use additional transistors to. The thesis comparison of cmos xor and xnor gate design by makara tang has been examined and approved by the following examination committee. In present work a new xnor gate using three transistors has been presented, which shows power dissipation of 550. A new design 6t full adder circuit using novel 2t xnor gates. As we know, optical waveguides are the key elements of photonic devices that perform guiding, coupling, switching, splitting, multiplexing, and demultiplexing of optical signals. Using dtl diode transistor logic we can implement xor and xnor logic functions with a minimum number of discrete components. A high output 1 results if both of the inputs to the. An nmos switch is on when the controlling signal is high and is off when the controlling signal is low. The first step in the synthesis of the logic gate is to derive the pulldown etwork as shown in figure 6.
From the above examples and discussion, we conclude that we can construct the main logic functions and, or, and not using transistors. Xnor gate ic of xor gate and8408 and8408d xor schmitt trigger create pulse ullga8 package frequency doubler ic xnor comparator using 2 xor gates. This nand gate using transistors circuit simulates the operation of a two or more inputs nand gate. Request pdf new 4transistor xor and xnor designs exclusiveor and exclusivenor gates are important in digital circuits. All the gates have their own identical logical function. Anne bracy cs 3410 computer science cornell university the slides are the product of many rounds of teaching cs 3410 by professors weatherspoon, bala, bracy, and sirer. In this gate if the b input is low then left nmos transistor is on and the logic value of a is copied to the output f. In which we have used one npn transistor, 4 diodes and the resistor between diode bridge and npn is used in series configuration because bjts operates on input current, not input voltages. Is it possible to design a switch circuit with xnors.
Calculations are done by utilizing a new subcircuit model for simulating the rthemt in the spice simulator. In present work a new xnor gate using three transistors has been presented, which shows. Figure below shows the implementation of xor function using pass transistors. Most logic gates have two inputs and one output and are based on boolean algebra. Digital logic or gate digital gates electrical technology. Three and five stages ring vcos have been designed using proposed xnor delay cell as shown in figures 3a and b. Hi guys, in this tutorial i will show you some npn transistor based logic gates. Digital circuitsnor logic wikibooks, open books for an. Pdf voltage controlled ring oscillator design with novel. Transistor and logic gates laboratory instruction today you will learn how to use a transistor to amplify a small ac signal as well as using it as a switch to construct digital logic circuits.
Digital logic gates nand and nor are called universal logic gate because we can construct all other logic gates using nand gate or nor gate alone. Introduction the ta will show you the emitter, base and collector for the transistor. The use of transistors for the construction of logic gates depends upon their utility as fast switches. The xor xnor gate has also many applications in digital circuits design. When we need to design logic circuits operating for higher than standard supply voltages, such as 30 and 24v, we can implement it by using regulators with standard logic family and interfacing it through level shifters. Since we will be using these functions or gates in future designs, we will give them symbols so that we dont have to draw all the transistors and all the connections each time we want to use say an or gate. Comparison of cmos xor and xnor gate design makara tang b. Proposed xorxnor gate circuit the xor and xnor gate functions are shown in table 1 and denoted by. Transistorlevel optimization of three input xorxnor gate. Xor and xnor functions using discrete electronics components. How to perform an xor function using a transistor quora.
Transistor level optimization of three input xor xnor gate using cmos logic design international journal of vlsi system design and communication systems volume. Single bit full adder design using 8 transistors with novel 3. Npn transistor xor gate circuit sully station technologies. From transistors to logic gates and logic circuits prof.
Design of a low power xnor gate using mtcmos technique. Simulations have been performed on the circuits along with 10 other xor gates. A pmos transistor acts as an inverse switch that is on when the controlling signal is low and off when the controlling signal is high. What you need a breadboard a bunch of 5k and 10k resistors, and transistors a led you can use any npn type transistor for example 2n3904, bc547, bc548, bc549 etc. Design and construct cmos xor and xnor gates using.
A general method in synthesis of passtransistor circuits. In present work a new xnor gate using three transistors has been. A new structure for an exclusiveor xor gate based on the resonanttunneling high electron mobility transistor rthemt is introduced which comprises only an rthemt and two fets. Schematic of xnor gate using diodes and bjt npn transistor is given below. Implementation of xor and xnor using optibpm the xor and xnor logic gates can be implemented using the combination of two mzi structures in which the signal can. Transistorlevel optimization of three input xor xnor gate using cmos logic design international journal of vlsi system design and communication systems volume. Instead, eda tools are used to convert the description of a logical circuit to a netlist of complex gates standard cells or transistors full custom approach.
A new 5 transistor xor xnor circuit based on the pass transistor logic. Design and construct cmos xor and xnor gates using cmos. Novel design methodology for highperformance xorxnor. Lowpower and fast full adder by exploring new xor and. So that when both inputs are 1, the and gate will activate the transistor, which will force the output to zero. As the basic and gate implements the boolean addition, while or gate implements boolean multiplication and not implements inversion function, there is no such boolean function defined by the xnor. This gdi based design provides improvements in several areas such that static power dissipation, design intricacy, logic level swing. The operation of exclusive nor gate is reciprocal to the exclusive or gates operation. Many circuits have been proposed to implement xor xnor gate, which a few examples of the most efficient ones are shown in fig. Full adder using xor xnor ptl cell with 16 transistors is reported in 4. Hence a nor gate is made up from a or gate which is followed by an inverter.
The results show that the new xor xnor gates consistently consume less. Multiple series transistors draw poly gates sidebyside. Voltage controlled ring oscillator design with novel 3 transistors xnor xor gates. To rectify this behavior, we propose a novel design methodology. A new xor structure based on resonanttunneling high. Cmos exor gate using gates as well as transistors youtube. A logic gate is a building block of a digital circuit. The xnor gate sometimes xornt, enor, exnor or nxor and pronounced as exclusive nor is a digital logic gate whose function is the logical complement of the exclusive or gate. By the combination of these gates, we can obtain any boolean or logical functions or logical function. Alternatively, the 4gate version of the xnor gate can be used with an inverter. Pdf a new 5transistor xorxnor circuit based on the pass.
Multiple series transistors draw poly gates sidebyside part. The main advantage of using transmission gate design is that it passes both 0s and 1s effectively as follows. Xor gate sometimes eor, or exor and pronounced as exclusive or is a digital logic gate that gives a true 1 or high output when the number of true inputs is odd. What is logic gate and, or, xor, not, nand, nor and xnor. Electrical engineering, portland state university 1997. Analysis of conventional cmos and finfet based 6t xorxnor. I accomplised this using a transistor as a switch, with its base driven by an and gate on the two inputs. It is based on the study of high speed, low power, and. Design of a low power xnor gate using mtcmos technique 703 consumed regardless of transistor switching.
From transistors to gates to logic circuits logic gates from transistors truth. When the baseemitter diode is turned on enough to be driven into saturation, the collector voltage with respect to the emitter may be near zero and can be used to construct gates for the ttl logic family. However, for certain input combinations, they give bad. In our proposed design we use gate diffusion input gdi based xnor gate which uses only 4 transistors 7. Cmos or gate using 4 transistors electrical engineering. Pdf a new 5transistor xorxnor circuit based on the. Measure propagation delay of xor gate measure propagation delay of xnor gate compare a spice simulation to the measured output values. By adding transistors to the design and combining the xor and xnorgates, we obtain a new circuit that exhibits better performance. What exactly does a 10 transistor xor gate look like. Every implementation ive seen uses 6 transistors, with the output of a nor circuit used as the input to an inverter circuit. So the xor gate can be considered as an or gate, plus an and gate, plus a. Jan 25, 2015 this feature is not available right now. A new 5transistor xorxnor circuit based on the pass transistor logic. The operation of exclusive nor gate is reciprocal to the exclusive or gate s operation.
Pdf single bit full adder design using 8 transistors. Exclusiveor and exclusivenor gates are important in digital circuits. Nand gate can be built using 4 mosfets 2nmos and 2pmos. New 4transistor xor and xnor designs ieee conference. Is it possible to design a switch circuit not a gate circuit using xnor s truth table value. Request pdf new 4 transistor xor and xnor designs exclusiveor and exclusivenor gates are important in digital circuits. Hybrid fas are made of two modules, including 2inputxorxnor or simultaneous xorxnor gate and 2to1 multiplexer 21mux gate. From transistorsto logic gates and logic circuits prof. Aug 21, 2017 i prepared xnor gate using 4 nor gates and xor gate using 5 nor gate using 2 methods. Individually, this is how we build a not gate using a transistor. Details of the design, input, and output values and margins, delay of each transition, maximum operating. This paper contrasts and evaluates the performance of conventional cmos and finfet based xor xnor circuit design. Proposed xorxnor gate circuit in fig 7, the proposed circuit design of xorxnor gate using. Full adder design with 10 transistors using xor xnor gates is also reported in 6.
From switches to transistors, logic gates and logic circuits hakim weatherspoon cs 3410, spring 20. The twoinput version implements logical equality, behaving according to the truth table to the right, and hence the gate is sometimes called an equivalence gate. Design of basic logic gates using nor gate not, or and. From switches to transistors, logic gates and logic circuits hakim weatherspoon cs 3410, spring 20 computer science cornell university see.
Pass transistor logic xor gate using pass transistor logic. The truth table of xor gate is as shown in table below. A general method in synthesis of passtransistor circuits d. Nand not and, nor not or, xor, and xnor not xor later building functions. If both inputs are false 0low or both are true, a false output results. Voltage controlled ring oscillator design with novel 3. The example transistor xor gate circuit is implemented here using pn2222a npn transistors a variant of the 2n2222a but many common npn bipolar junction transistors. Single bit full adder design using 8 transistors with. This paper proposes a new set of low power 4 transistor xor xnor gates. Transistor level optimization of three input xor xnor gate using. Analysis of conventional cmos and finfet based 6t xor. As can be seen in the logic diagram below, the xor gate is built by combining three more simple gates, the or gate, the nand gate and the and gate to produce the desired result. Can an or gate be implemented using 4 cmos transistors. Nmos switch closes when the gate input is high remember nmos transistors pass a strong 0 but a weak 1 ab xy x y if a and b xy a b x y if a or b comp103l7.