Request pdf new 4transistor xor and xnor designs exclusiveor and exclusivenor gates are important in digital circuits. Using five 2 input nand gate as shown in figure below we may realize 4 input nand gate. Many circuits have been proposed to implement xor xnor gate, which a few examples of the most efficient ones are shown in fig. To rectify this behavior, we propose a novel design methodology. Transistor level optimization of three input xor xnor gate using. Is it possible to design a switch circuit not a gate circuit using xnor s truth table value. Can an or gate be implemented using 4 cmos transistors. Figure below shows the implementation of xor function using pass transistors. 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. Details of the design, input, and output values and margins, delay of each transition, maximum operating. Design of a low power xnor gate using mtcmos technique. 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. Is it possible to design a switch circuit with xnors. The xor xnor gate has also many applications in digital circuits design.
The first solution is to add a feedback between the xor and xnorgate and use additional transistors to. Design of basic logic gates using nor gate not, or and and. By the combination of these gates, we can obtain any boolean or logical functions or logical function. What exactly does a 10transistor xor gate look like. The truth table of xor gate is as shown in table below. A general method in synthesis of passtransistor circuits d. Physical realization of a 4terminal mosfets tunomyo lsa gate is intersection of active, poly, and nselect. Request pdf new 4 transistor xor and xnor designs exclusiveor and exclusivenor gates are important in digital circuits.
Mathematics, portland state university 1997 minor b. 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. Full adder using xor xnor ptl cell with 16 transistors is reported in 4. Construction and working mechanism of xnor gate xnor gate using bjt and diodes. Full adder design with 10 transistors using xor xnor gates is also reported in 6. Cmos or gate using 4 transistors electrical engineering. 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. New 4transistor xor and xnor designs ieee conference. Xor and xnor functions using discrete electronics components. An nmos switch is on when the controlling signal is high and is off when the controlling signal is low. A new 5 transistor xor xnor circuit based on the pass transistor logic.
The thesis comparison of cmos xor and xnor gate design by makara tang has been examined and approved by the following examination committee. Logic gates a b out 0 0 0 0 1 1 1 0 1 1 1 1 a b out. Voltage controlled ring oscillator design with novel 3. Calculations are done by utilizing a new subcircuit model for simulating the rthemt in the spice simulator. 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. Electrical engineering, portland state university 1997. The first step in the synthesis of the logic gate is to derive the pulldown etwork as shown in figure 6. The use of transistors for the construction of logic gates depends upon their utility as fast switches. Novel design methodology for highperformance xorxnor.
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. Xnor gate ic of xor gate and8408 and8408d xor schmitt trigger create pulse ullga8 package frequency doubler ic xnor comparator using 2 xor gates. Alternatively, the 4gate version of the xnor gate can be used with an inverter. At any given moment, every terminal is in one of the two binary conditions false high or true low. The operation of exclusive nor gate is reciprocal to the exclusive or gate s operation. A new xor structure based on resonanttunneling high. In present work a new xnor gate using three transistors has been presented, which shows power dissipation of 550. This nand gate using transistors circuit simulates the operation of a two or more inputs nand gate. 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. So the xor gate can be considered as an or gate, plus an and gate, plus a. How to perform an xor function using a transistor quora. Voltage controlled ring oscillator design with novel 3 transistors xnor xor gates.
All the gates have their own identical logical function. Three and five stages ring vcos have been designed using proposed xnor delay cell as shown in figures 3a and b. Design of a low power xnor gate using mtcmos technique 703 consumed regardless of transistor switching. A new design 6t full adder circuit using novel 2t xnor gates. 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. 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. In present work a new xnor gate using three transistors has been presented, which shows.
From switches to transistors, logic gates and logic circuits hakim weatherspoon cs 3410, spring 20. The results show that the new xor xnor gates consistently consume less. What exactly does a 10 transistor xor gate look like. 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. Exclusiveor and exclusivenor gates are important in digital circuits. Proposed xorxnor gate circuit the xor and xnor gate functions are shown in table 1 and denoted by. Multiple series transistors draw poly gates sidebyside part. The operation of exclusive nor gate is reciprocal to the exclusive or gates operation. Nand gate can be built using 4 mosfets 2nmos and 2pmos. Analysis of conventional cmos and finfet based 6t xorxnor.
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. From transistors to gates to logic circuits logic gates from transistors truth. A general method in synthesis of pass transistor circuits. 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. 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. 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. Pdf single bit full adder design using 8 transistors. From switches to transistors, logic gates and logic circuits hakim weatherspoon cs 3410, spring 20 computer science cornell university see. A high output 1 results if both of the inputs to the. Pdf a new 5transistor xorxnor circuit based on the pass.
A logic gate is a building block of a digital circuit. Introduction the ta will show you the emitter, base and collector for the transistor. Single bit full adder design using 8 transistors with. Transistor level optimization of three input xor xnor gate using cmos logic design international journal of vlsi system design and communication systems volume. This paper proposes a new set of low power 4 transistor xor xnor gates. If both inputs are false 0low or both are true, a false output results.
Lowpower and fast full adder by exploring new xor and xnor gates. Jan 25, 2015 this feature is not available right now. The main advantage of using transmission gate design is that it passes both 0s and 1s effectively as follows. Single bit full adder design using 8 transistors with novel 3 transistors xnor gate manoj kumar 1, sandeep k.
What is logic gate and, or, xor, not, nand, nor and xnor. 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. Individually, this is how we build a not gate using a transistor. Digital circuitsnor logic wikibooks, open books for an. Pass transistor logic xor gate using pass transistor logic. Multiple series transistors draw poly gates sidebyside. Pdf a new 5transistor xorxnor circuit based on the. 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. Design of basic logic gates using nor gate not, or and. This gdi based design provides improvements in several areas such that static power dissipation, design intricacy, logic level swing. Proposed xorxnor gate circuit in fig 7, the proposed circuit design of xorxnor gate using.
Comparison of cmos xor and xnor gate design makara tang b. Logic gates are basically are group of three basic logic gates specifically called as not, and and or gate. Aug 21, 2017 i prepared xnor gate using 4 nor gates and xor gate using 5 nor gate using 2 methods. Design and construct cmos xor and xnor gates using. Hybrid fas are made of two modules, including 2inputxorxnor or simultaneous xorxnor gate and 2to1 multiplexer 21mux gate. Design and construct cmos xor and xnor gates using cmos. Schematic of xnor gate using diodes and bjt npn transistor is given below. It is based on the study of high speed, low power, and. 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. Single bit full adder design using 8 transistors with novel 3. Most logic gates have two inputs and one output and are based on boolean algebra. From the above examples and discussion, we conclude that we can construct the main logic functions and, or, and not using transistors. Every implementation ive seen uses 6 transistors, with the output of a nor circuit used as the input to an inverter circuit.
Hi guys, in this tutorial i will show you some npn transistor based logic gates. However, for certain input combinations, they give bad. In present work a new xnor gate using three transistors has been. As we know, optical waveguides are the key elements of photonic devices that perform guiding, coupling, switching, splitting, multiplexing, and demultiplexing of optical signals. I accomplised this using a transistor as a switch, with its base driven by an and gate on the two inputs. Transistorlevel optimization of three input xorxnor gate. Hence a nor gate is made up from a or gate which is followed by an inverter.
The circuit would have two ntype transistors in parallel in the pullup network, and two ptype transistors in series for the pulldown network. Xor and xnor circuits based on the pass transistor logic were used which results in the design of 14t full adder 5 as shown in fig. Simulations have been performed on the circuits along with 10 other xor gates. So that when both inputs are 1, the and gate will activate the transistor, which will force the output to zero. Digital logic or gate digital gates electrical technology. Pdf voltage controlled ring oscillator design with novel. 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. Npn transistor xor gate circuit sully station technologies. 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. So we need not, and and or gates to form an xor circuit. From transistors to logic gates and logic circuits prof. Lowpower and fast full adder by exploring new xor and.
In our proposed design we use gate diffusion input gdi based xnor gate which uses only 4 transistors 7. Analysis of conventional cmos and finfet based 6t xor. Using dtl diode transistor logic we can implement xor and xnor logic functions with a minimum number of discrete components. This paper contrasts and evaluates the performance of conventional cmos and finfet based xor xnor circuit design. A new 5transistor xorxnor circuit based on the pass transistor logic. From transistorsto logic gates and logic circuits prof. Transistorlevel optimization of three input xor xnor gate using cmos logic design international journal of vlsi system design and communication systems volume. Nand not and, nor not or, xor, and xnor not xor later building functions. Measure propagation delay of xor gate measure propagation delay of xnor gate compare a spice simulation to the measured output values. A general method in synthesis of passtransistor circuits. Cmos exor gate using gates as well as transistors youtube. 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. By adding transistors to the design and combining the xor and xnorgates, we obtain a new circuit that exhibits better performance. Sep 07, 2015 the word nor gate is just an short form of the not and or gate combination.
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