In vlsi technology, mos circuits have been widely used in many fields. In this video i will discuss how to design an xnor gate signal. The standard 4000 series cmos ic is the 4077, and the ttl ic is the 74266 although an opencollector implementation. This paper presents a comparative study of highspeed and lowvoltage full adder circuits. To be meaningful, the analysis program has to process a typ.
National central university ee6 vlsi design logic gate design 8input and gate approach comparison of approaches to designing an 8input and gate delay stage 1ns delay stage 2ns delay stage 3ns delay stage 4ns total delay spice ns 1 nd8inv 2 nd4nr2 3 nd2nr2 nd2inv 2. Aug 04, 2015 nand and nor gate using cmos technology by sidhartha august 4, 2015 12 comments for the design of any circuit with the cmos technology. Comparative performance analysis of xorxnor function based highspeed cmos full adder circuits issn. Build the xor xnor circuit shown in figure 3 on your solderless breadboard. Learn verilog first also know basics of matlab find way to understand logic simulation. The design considerations for a simple inverter circuit were presented in the previous chapter. These tools allow students, hobbyists, and professional engineers to design and analyze analog and digital systems before ever building a prototype. The thesis comparison of cmos xor and xnor gate design by makara tang has been examined and approved by the following examination committee. Nasa electronic parts and packaging nepp program 2008. Use the cd4007 cmos array for devices m 16 and one. The proposed design has consumed seven transistors as compared to 16 transistors in case of existing design. Jun 03, 2015 static cmos circuits use complementary nmos pulldown and pmos pullup networks to implement logic gates or logic functions in integrated circuits. Design, layout, and simulations of cmos nand, nor, xor gates and a fulladder.
A high performance adder cell using an xorxnor 3t design style is discussed. Cmos technology properties of microelectronic materials resistance, capacitance, doping of semiconductors 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. Some of the pcb design software also let you make schematic design in a single package. Jan 06, 2017 this paper concerns with the designing of xor gate based on 90nm technology by using transmission gates logic. Another inverter, m 9,10, inverts c to produce the cbar xnor output. The jed file is for configuring the home made cpld board. Exclusivenor xnor digital logic gate electrical technology. Cadence pspice technology offers more than 33,000 models covering various types of devices that are included in the pspice software. 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. But for nor, nand, xor gates, because there are more transistors in those gates, it looks like not easy to choose the values for wlp and wln.
How to size the pmos and nmos in nor nand xnor gates. Schematic and layout of a nand gate in lab 1, our objective is to. As uthephoton points out, xnor implemented in cmos isnt created by inverting the output of a nor gate i. The harris cd4077b contains four independent exclusivenor gates. Use the cd4007 cmos array for devices m 16 and one zvn2110a nmos and zvp2110a pmos for each of the two inverter stages m 7,8 and m 9,10. It covers less area compared to 16 transistors xnorxor with cmos circuit as well as less power with smaller delay. Fulltext cmos vlsi design of low power comparator logic circuits. Like nand circuit, this circuit can be analyzed by realizing that a low at any input turns on its corresponding pchannel mosfet and turns off its corresponding nchannel mosfet.
Tutorial on how to design a cmos nor layout using microwind design and simulation tool. There are several ways in which one can design a xor gate using mosfet. Why is it called an xnor gate and not an nxor gate. Online schematic capture lets hobbyists easily share and discuss their designs, while online circuit simulation allows for quick design iteration and accelerated learning about electronics. One of the most common uses for xor gates is to add two binary numbers. Cmos vlsi design of low power comparator logic circuits. Assume pmos on resistance is 2rn, nmos is rn, gate capacitance is cg and load capacitance is 2cg.
For 2input gate, it can be interpreted as when both of the inputs are same, then the output is high state and when the inputs are different, then the output is low state 0. The xor gate has been implemented and comparing on basis of semicustom and fully. Performance analysis of high speed hybrid cmos full adder. Which is the best software for practicing vlsi designing for.
Xnor gate also known as exclusivenor or exclusivenegative or gate is a logic gate which produces high state 1 only when there is an even number of high state 1 inputs. Static logic design of nand, nor, xor and xnor gates. Electric vlsi design system free and powerful cad system for chip design schematics, layout, drc, lvs, erc, etc. This video shows the nand gate and then the nor gate implemented on the home made cpld board. In this paper, we present a formal design method for balanced 3input xorxnor circuits in the hybridcmos logic style. Download pspice for free and get all the cadence pspice models. The truth table, derived directly from the xor truth table, uses an xor gate with one input tied to a signal named control.
Xnorgateusingpasstransistorlogic digitalcmosdesign cmosprocessingtechnology planarprocesstechnology,siliconcrystalgrowth, twintubprocess, waferformationanalog electronic circuits is exciting subject area of electronics. Figure 1 below shows the implementation of xor gate using 2input nand gates. A high performance adder cell using an xor xnor 3t design style is discussed. Both include four independent, twoinput, xnor gates. Lowpower and fast full adder by exploring new xor and xnor gates. Jan 06, 2017 in this video tutorial you can learn how to design xnor gate using micro wind software. 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 design. Our approach is based on hybrid design full adder circuits combined in a single unit. Some of these circuit design software let you create schematic design, while some let you design pcb. This paper also discusses a highspeed conventional full adder design combined with moscap majority function circuit in one unit to. I am using pmos and nmos to implement complement a, means that i am not using complement directly into the circuit.
Cmosxnorandxor digitalcmosdesign cmosprocessingtechnology planarprocesstechnology,siliconcrystalgrowth, twintubprocess, waferformationanalog electronic circuits is exciting subject area of electronics. Cmos circuit design, layout, and simulation, fourth edition. The xor gate has a lesserknown cousin called the xnor gate. Oct, 20 1 go through the video tutorial 4 and learn how to design schematiclayout for nand and nor gates. No further optimizations to the logic seem possible to this logic. Cmos xnor andxor digital cmos design cmos processingtechnology planarprocesstechnology,siliconcrystalgrowth, twintubprocess, waferformationanalog electronic circuits is exciting subject area of electronics. 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. I have created a truth table next the diagram based on my understanding of basic mosfet switching. A truth table of xor gate can easily be followed to get a.
The xnor gate sometimes enor, exnor or nxor and pronounced as exclusive nor is a digital logic gate whose function is the logical complement of the exclusive or xor gate. Xnor gates are represented in most ttl and cmos ic families. For inverter, we can size the wlp and wln according to vth, delay requirement. The design has been compared with earlier proposed 4t and 6t xor gates and a. Get familiar with the cadence virtuoso environment. It covers less area compared to 16 transistors xnor xor with cmos circuit as well as less power with smaller delay. For 2input gate, it can be interpreted as when both of the inputs are same, then the output is high state and when the inputs are different, then the output. The now obsolete 74s5 implemented four twoinput xorxnor gates or two threeinput xnor gates. This paper concerns with the designing of xor gate based on 90nm technology by using transmission gates logic. Lowpower and fast full adder by exploring new xor and xnor. Ben bitdiddle is the memory designer for the motoroil 68w86, an embedded automotive processor.
Nand and nor gate using cmos technology by sidhartha august 4, 2015 12 comments for the design of any circuit with the cmos technology. An xnor gate is an xor gate whose output is inverted. Comparative performance analysis of xor xnor function based highspeed cmos full adder circuits issn. The now obsolete 74s5 implemented four twoinput xor xnor gates or two threeinput xnor gates. The complete cmos implementation of xor gate is as shown in figure below. Cmos inverter circuit i cmos nand gate i cmos nor gate circuit. Supply voltage vdd and transistor size continue to scale smaller sizes with lower power dissipation and faster microprocessors. Both pcb footprints and schematic symbols are available for download in a vendor neutral format, which can then be exported to the leading eda cadcae design tools using the ultra librarian reader. Complementary metal oxide semiconductor cmos technology is advancing for microprocessors.
Next and if necessary we apply various correction mechanisms and. Similarly, we can realize an inverter using an xor gate by connecting one of the inputs to logic 1. Ila sharma102001 harsh magotra 102012 slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. As you can see, the only difference between these two symbols is that the xnor has a circle on its output to indicate that the output is inverted. 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. Isbn 9781119481515 design, layout, and simulation examples. The paper proposes the novel design of a 3t xor gate combining complementary cmos with pass transistor logic. Pdf design of adder logic cell with xor gate researchgate. The twoinput version implements logical equality, behaving according to the truth table to the right, and hence the gate is sometimes called an. Layout design analysis of xor gate by using transmission.
These freeware let you design digital circuits with a vast array of inbuilt components. Draw layout of a nand gate using cell library, then run a design rule check drc, extract. Electronic design automation eda is a category of software tools for designing electronic systems such as printed circuit boards and integrated circuits. Design of a reliable xorxnor circuit for arithmetic logic units. Hybrid fas are made of two modules, including 2inputxorxnor or simultaneous xorxnor gate and 2to1 multiplexer 21mux gate. Draw a schematic of a simple nand gate and simulate it. The implemented logic function or the logic gate is achieved through 2 modes of operation. In this methodology, designer utilize various basic cells, including three independent. Lab6 designing nand, nor, and xor gates for use to design full. 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. Someone please explain to me how the circuit below operates as nor gate. The exclusiveor xor and exclusivenor xnor functions are popular gates in microprocessors. Comparative performance analysis of xorxnor function.
Big names in eda software are synopsys, cadence, mentor, and magma here is some of the software typically involved in a standardcell asic flow. Xnorgateusingpasstransistorlogic digitalcmosdesign. The two input xnor gate can be constructed by combining pdn and pun as shown in figure. And or nand xor xnor gate implementation and applications. The developed logic has been design using 65nm technology on microwind3. In this paper, the authors present the realization of full adder designs using complimentary cmos design, complimentary passtransistor logic cpl design and xorxnor design in a single unit. Introduction 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. Xnor gateusingpasstransistorlogic digital cmos design cmos processingtechnology planarprocesstechnology,siliconcrystalgrowth, twintubprocess, waferformationanalog electronic circuits is exciting subject area of electronics. Apr 12, 2011 proposed circuit for fast xor xnor operations presented by. In our approach, we start with selecting a basic cell including 3input and two outputs. Hdl simulators read an rtl description of the design typically written in verilog or vhdl and mimic the behavior of the hardware described by the rtl. Abstract in this paper, a systematic design methodology based on pass transistor and transmission gate in the category of hybridcmos logic style is proposed and used for design balanced 3input xorxnor circuits. Comparative performance analysis of xorxnor function based.
Static cmos circuits use complementary nmos pulldown and pmos pullup networks to implement logic gates or logic functions in integrated circuits. The xor gate can be constructed by connecting inverter at the output stage of two input xnor gate. Here, pchannel mosfets q 1 and q 2 are connected in series and nchannel mosfets q 3 and q 4 are connected in parallel. Static logic is a design methodology in integrated circuit design where there is at all times some mechanism to. The cd4070b and cd4077b provide the system designer with a means for direct implementation of the exclusiveor and exclusivenor functions, respectively. Xnor based full adder electric vlsi design software view the circuit consist of one xnor block, one inverter block, one multiplexer based transmission gate block and one pass transistor based transmission gate block. In this video tutorial you can learn how to design xnor gate using micro wind software. A useful application of the xor function is the controlled inverter circuit illustrated below in fig. Cmosxnorandxor digitalcmosdesign electronics tutorial. Build the xorxnor circuit shown in figure 3 on your solderless breadboard. Its more efficient to create it directly, using the same number of gates as nor itself 8, versus 10 for notxor as shown here. How many transistors do i need to design a cmos xor gate and. Lab6 designing nand, nor, and xor gates for use to.
Advantages and disadvantages of a dynamic cmos circuit over a. What is the best software for vlsi ic chip layout designing. Here is a list of best free circuit design software for windows. The xorxnor gate is the major consumer of power in the fa cell.