Build the xorxnor circuit shown in figure 3 on your solderless breadboard. The schematic of xor gate using cmos logic is shown in figure 4. And or nand xor xnor gate implementation and applications. The cd4030b types are supplied in 14lead hermetic dualinline ceramic packages f3a suffix, 14lead dualinline plastic packages e suffix, 14lead smalloutline packages m, mt, m96, and nsr suffixes, and 14lead thin shrink. The above drawn circuit is a 2input cmos nand gate. This paper proposes a new design of xor gate using six transistors for low power application. The lab description of using electric software to design xor.
Single bit full adder design using 3 transistor xor gate is presented in ref 8. A ptype mosfet can be modeled as a switch that is closed when the input voltage is low 0 v and open when the input voltage is high 5 v. For more info, read the xilinx user guide found in help tab. Will be happy to discuss other ways of implementing xor using mosfets. If both of an xor gates inputs are false, or if both of its inputs are true, then the output of the xor gate is false. Lab 6 design, layout, and simulation of cmos nandnorxor. The xor circuit with 2 inputs is designed by using and, or and not gates is shown above. For the design of any circuit with the cmos technology. The twoinput nor2 gate shown on the left is built from four transistors. Cmos realization of nand and xor in xilinx if you setup nand or nor gates in programmable logic, the observed dynamic power dissipation wont have much to do with the basic logic operation, its mainly consumed in io cells.
Boolean equation circuit element gate university of texas at austin cs310 computer organization spring 2009 don fussell 3 truth table brute force io specification grows exponentially with number of inputs. There are several ways in which one can design a xor gate using mosfet. Boolean logic in cmos university of texas at austin. Aug 04, 2015 in case of nand gate, 3 pmos will be connected in parallel and 3 nmos will be connected in series, and other way around in case of 3 input nor gate. The mc74vhct86a is an advanced high speed cmos 2input exclusiveor gate fabricated with silicon gate cmos technology. May 27, 2019 the ttl transistortransistor logic and cmos complementary metal oxide semiconductor technology is used to designed xnor gate.
The cmos xor block represents a cmos xor logic gate behaviorally. If both the inputs are same, then the output is low. Fpga design using vhdl, vlsi design using electric, spice modelling using lt spice, pcb designing using eagle, robotics and much more. And or nand xor xnor gate implementation and applications dc supply voltage, ttl logic levels, noise margin, power dissipation boolean addition, multiplication, commutative law, associative law, distributive law, demorgans theorems. Cmos gates nand gnd a b vdd 11 0 10 1 1 0 b 0 1 0 1 a out. From transistorsto logic gates and logic circuits prof.
This circuit occupies larger area and consumes more power are the disadvantages of. This circuit was created by a member of the community and has no affiliation to the circuit diagram project. Mathematics, portland state university 1997 minor b. Design, layout, and simulations of cmos nand, nor, xor gates and a fulladder. The output of a xor gate is equal to 1 if the two inputs are both different, and is 0 if they both have the same logic value. This article is about xor in the sense of an electronic logic gate e. On the left are two inverters while the right half contains the majority of the xor gate.
In order for this to be a cmos xor gate, transistor connected to vcc needs to be ptype, making the right two transistors into an inverter. For example, in many of the popular logic families, such as ttl and traditional cmos. In fully automatic custom layout design of cmos is developed from dsch. To construct the logic functions in this lab activity you will be using the cd4007 cmos array and discrete nmos and pmos transistors zvn2110a nmos and zvp2110a pmos from the. The xor gate has been implemented and comparing on basis of semicustom and fully. The ttl transistortransistor logic and cmos complementary metal oxide semiconductor technology is used to designed xnor gate. Physical structure of cmos devices and circuits pmos and nmos devices in a cmos process nwell cmos process, device isolation fabrication processes physical design layout layout of basic digital gates, masking layers, design rules sslecoocos pr planning complex layouts euler graph and stick diagram part i.
The harris cd4070b contains four independent exclusiveor gates. The fundamental building blocks of cmos circuits are ptype and ntype mosfet transistors. Design and implementation of full subtractor using cmos 180nm. One of the most popular ic for xnor gate is 74hc266n which is a quad two inputs xnor gate ic which means that this ic contains four independent two input xnor gates. Lab6 designing nand, nor, and xor gates for use to design. Jul 29, 20 gate ec electronics and communications engineering 20 problems and solutions electron devices analog circuits digital circuits 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000. How many transistors do i need to design a cmos xor gate. It achieves high speed operation similar to equivalent bipolar schottky ttl while maintaining cmos low power dissipation. Cmos complementary metaloxidesemiconductor technology is used predominantly to create digital circuitry. The output of 2 input xor gate is high only when one of its inputs are high. The output of an xor gate is true only when exactly one of its inputs is true. For example, a single cd4007 can be used to make three inverters, an inverter plus two transmission gates, or other complex logic functions such as nand and nor gates. Logic design more than one logic circuit can implement same logic function.
Similarly, we can realize an inverter using an xor gate by connecting one of the inputs to logic 1. On pspice, ive created a transistorlevel schematic for what i mean by 2input cmos xor gate the top voltage source is simply supposed to be vdd of 5v, ignore the missing connection. Introduction a xor gate is an electronic logic circuit in the world of technology the. Schematic of xor using cmos logic by using transmission gates logic, the number of transistors is reduced from the conventional cmosxor gate. Pdf design of adder logic cell with xor gate researchgate. Efficient xor gate designing using vlsi techniques ijett. Just build a project and using the verilog design after synthesizing and implementing the code, you will get an access to the design summary which contains all the information you need. Here is my schematic deisng, icon, and layout of an xor gate. A power efficient circuit topology is proposed to implement a lowvoltage cmos 2input passtransistor xor gate. Xor systems is a trading name for xor software ltd.
The new xor gate has been compared with previous design in term of power, delay and powerdelay product pdp. Click the input switches or type the a,b and c,d bindkeys to control the two gates. The jed file is for configuring the home made cpld board. I am using pmos and nmos to implement complement a, means that i am not using complement directly into the circuit. Now all i need to know is how to align the transistors to make a 3input version of exactly this, lol. The complete cmos implementation of xor gate is as shown in figure below. Specifically, learn how to combine cmos transmission gates and cmos inverters to build transmission gate exclusive or xor and xnor logic functions. Cmosxnorandxor digitalcmosdesign electronics tutorial. Introduction to xnor gate projectiot123 technology.
A single buffer is only one gate, not a combination. Jan 06, 2017 this paper concerns with the designing of xor gate based on 90nm technology by using transmission gates logic. As shown in the truth table below, out is opposite to the value of b. Lab6 designing nand, nor, and xor gates for use to. You may do so in any reasonable manner, but not in. So, xor gate using mosfets or more appropriately cmos logic is as follows. Cmoslogic digital logic families electronics tutorial. In order to design 2input nand, nor, xor and xnor gates for equal rise and fall time, it is necessary to first design an inverter with equal rise and fall time. This applet demonstrates the static twoinput nor and or gates in cmos technology. Inverters and transmission gates are particularly useful for building transmission gate exclusive or xor and xnor logic functions. Cmos xor gate 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. Requires propagation through two gates one set of gates is to generate inverted signals for the cmos logic.
Problem on complex cmos logic gates gate ece 2012 solved. Jul 14, 2015 the exor gate is defined as, the hybrid logic gate with 2 or more inputs to perform the exclusive disjunction operation. Keep the nmos size the same, but change the pmos to 2010. This video shows the nand gate and then the nor gate implemented on the home made cpld board.
A truth table of xor gate can easily be followed to get a mos based circuit for the gate. Xor gate using basic logic gates if a specific gate is not available directly, we will design that gate by using multiple gates. V v satyanarayana pithani, software engineer at splenta systems pvt. The schematic of all the logic gates implemented using cmos 180nm technology is shown in fig. The xor gate is simulated using cadence virtuoso analog environment in 65nm complementary metal oxide. In todays modern world complementary metal oxide semiconductor cmos design techniques are used for designing so that power, area, delay may be. We need parallel or series connections of nmos and pmos with a nmos source tied directly or indirectly to ground and a pmos source tied directly or indirectly to v dd.
The exor gate is defined as, the hybrid logic gate with 2 or more inputs to perform the exclusive disjunction operation. If we already have xor digital gate, why dont we have xand exclusiveand gate. Xor gate the schematic for the xor gate can be seen below. Xor software ltd is a registered company in england and wales. Xor schematic and icon view as seen in the layout below, 3 sframes were used to contain the. Xilinx project navigator would only give you the estimate of power consumption in fpga. Xor gate also known as exclusive or gate is a logic gate which produces high state 1 only when there is an odd number of high state 1 inputs.
The cd4030b provides the system designer with a means for direct implementation of the exclusiveor function. The two input xnor gate can be constructed by combining pdn and pun as shown in figure. Electrical engineering, portland state university 1997 a thesis presented to the faculty of the ogi school of science and engineering at oregon health and science university in partial fulfillment of the. From top view of layout, can determine how many squares of the layer are present. Comparison of cmos xor and xnor gate design makara tang b. This file is licensed under the creative commons attributionshare alike 3.
An exor gate can be designed by using basic logic gates like nand gate and nor gate. Figure 1 shows the truth table for a 2input xor gate where a and b are the two inputs and out is equal to xor of a and b. This paper concerns with the designing of xor gate based on 90nm technology by using transmission gates logic. Exclusiveor xor digital logic gate electrical technology. Permission is granted to copy, distribute andor modify this document under the terms of the gnu free documentation license, version 1. A basic cmos structure of any 2input logic gate can be drawn as follows. The dsch program is a logic editor and simulation then its verilog file is generated. Two transistor xor gate based single bitfull adder design. Static logic is a design methodology in integrated circuit design where there is at all times some mechanism to drive the output either high or low. Also create a fulladder implemented by 3 nands and 2 xors.
The harris cd4077b contains four independent exclusivenor gates. If we observe carefully, out equals b when a is 0 and b when a is 1. An xor gate sometimes referred to by its extended name, exclusive or gate is a digital logic gate with two or more inputs and one output that performs exclusive disjunction. This involves compensating for the difference in electron and hole mobilities.
For 2input gate it can be interpreted as when both of the inputs are different, then the output is high state 1 and when the inputs are same, then the output is low state 0. Lab6 designing nand, nor, and xor gates for use to design full. Cmos full adder circuit design based on transmission gate using 20 transistors is as shown in fig 1. Im currently doing the practice problems for cmos vlsi design 4th edition. The same pattern will continue even if for more than 3 inputs. For xor in the purely logical sense, see exclusive or. This design aims to minimize power dissipation and reduce transistor count while at. 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.
The xor gate can be constructed by connecting inverter at the output stage of two input xnor gate. The block output logic level is high if the logic level of exactly one of the gate inputs is 1. Static logic design of nand, nor, xor and xnor gates. The aim of this experiment is to design and plot the dynamic characteristics of 2input nand, nor, xor and xnor gates based on cmos static logic introduction. Design and implementation of full subtractor using cmos. Layout design analysis of xor gate by using transmission gates. Further scaling up of this type of multiinput circuit will require. As with the nor gate, the pmos are 202 and the nmos are 102. Lab 6 design, layout, and simulation of cmos nandnor. You can use nand gate, transmission gates, pass transistor. Use the cd4007 cmos array for devices m 16 and one. Cmos notation ntype ptype gate input controls whether current can flow. Schematics of a inverter b 2 input and gate c 2 input or gate d 2 input xor gate. The cd4070b and cd4077b provide the system designer with a means for direct implementation of the exclusiveor and exclusivenor functions, respectively.