A transistor is an electronic device that has three ends. The result is in some cases conceptual simplification, but the cmos inverters strict logichighlogiclow output characteristic is lost. Pass transistor logic adapted from rabaeys digital integrated circuits, second edition, 2003 j. Pdf a high speed 8 transistor full adder design using. A novel 1bit full adder design using dcvsl xorxnor gate and.
Lower noise margin is the disadvantage of pass transistor logic. Introduction conventional static cmos has been a technique of choice in most processor design 1. Problems design 4 to 1 multiplexor using transmissiongates. On one hand, the imperfect highvoltage levels, resulting from the imperfect voltage transmission by singlemos switches, at some selected intermediated circuit nodes are used to reduce the signal swing. Cmpen 411 vlsi digital circuits spring 2011 lecture 07. Sep 17, 2016 realizing constructing a cmos pass gate cmos transmission gate from transistors. Complementary passtransistor logic cpl with 32 transistors having high power dissipation and better driving capability is reported in 4. Xor gate is wildly used in half adder, subtractor and multiplier. The main motive of this paper is to determine the comparative study of power, delay. Single bit full adder design using 8 transistors with. Simple xor makes it attractive for structures like adders.
The operation of a transistor could be explained by making an analogy to faucets. The ntype pass transistor can pass an input signal when a logic 1 is biased on the gate, and it is turned off when a logic 0 is biased on the gate. Pdf a new 5transistor xorxnor circuit based on the. Introduction to passtransistor logic technical articles. He was born in lincoln, england and he was the son of a shoemaker. From transistors to functions for the purpose of this class, we will consider transistors to be the basic building blocks of computer hardware. Digital integrated circuits combinational logic prentice hall 1995 overview static cmos conventional static cmos logic ratioed logic pass transistortransmission. Logic families comparison for xor and nand of full adder in this section, a description for the different logic families to implement xor and nand gates of the full adder gate level implementation that was agreed upon in the previous section. The paper describes how the logic functions can be efficiently and optimally built using passtransistor logic. The current drive of the transistor gatetosource voltage is reduce significantly as v.
Just like a transistor, a faucet is connected to a source the water company, the faucet drains in a sink, and the flow of water through the faucet is controlled by a gate the knob. Double passtransistor logic dpl dpl a b b b a c c o q qb n1 p1 n2 p2 n1 p1 p2 b b a s s o xor sum same number of n and pchannel devices uc berkeley ee241 b. Two transistor xor gate based single bitfull adder design. Transmission gate an overview sciencedirect topics. Abstractpasstransistor logic ptl uses pass transistors to directly pass logic.
Pdf dualthreshold passtransistor logic design researchgate. Pnp transistors as commonemitter switches duration. Andnand, ornor, and xorxnor in each of these families. Section 2 gives an overview of three conventional pass transistor logic families complementary pass transistor logic cpl, double pass transistor logic dpl, and dual value logic dvl. Full adder design with 10 transistors using xor xnor gates is also reported in 6. Passtransistor logic switch network a b b reduced number of transistors no static power consumption. Vlsi design pass transistor logicpass transistor logic adapted from rabaeys digital integrated circuits, 2002, j. Note that the caret does not denote logical conjunction and in these languages, despite the similarity of symbol. Section 2 gives an overview of three conventional passtransistor logic families complementary passtransistor logic cpl, double passtransistor logic dpl, and dual value logic dvl. The advantage of pass transistor logic ptl is that. Pdf this paper introduces passtransistor logic design with dualthreshold voltages. Design of high performance multipleinput passtransistor. An eight transistor full adder has been designed using the proposed threetransistor xor gate and its performance has. Logic gates digital circuit that either allows signal to pass through it or not used to build logic functions seven basic logic gates.
In 2 a 16 transistors full adder cell with xorxnor, pass transistor logic ptl and transmission gate is reported. The implemented functions are arithmetic, xor and mux based circuits. Here the output of first xor gate is applied as a input to the next xor gate, second xor gate has c. In this lecture, we will talk about another way to implement logic functions using transistors. Passtransistor logic switch network a b b reduced number of transistors. V s will initially charge up quickly, but the tail end of the transient is slow. Comparison of equivalent resistance for cpl, cmos, and. The hybrid adder is designed using dcvsl gates because these can produce both complementary and true outputs using single gate architecture. Transistor transistor logic ttl family one basic function of ttl ic is as a complimenting switch or inverter. Indeed, designing highspeed lowpower circuits with. Comparative performance analysis of xorxnor function based highspeed cmos full. Design of efficient passtransistor binary alu asee.
Comparative performance analysis of xorxnor function based. Xor has the worstcase karnaugh mapif implemented from simple gates, it requires more transistors than any other function. If the faucet knob gate is turned on water flows from the source to the sink, otherwise if the faucet. Index terms adder circuits, cpl, complementary cmos, lowvoltage lowpower logic styles, pass. Topology of 2 input subnanowatt xor gate in 65nm cmos. Readers are encouraged to try implementing other boolean functions with this approach. Comparative performance analysis of xorxnor function. For low power applications pass transistor logic ptl is best suitable technique and explanation was given in.
Passtransistor logic ptl, also known as transmissiongate logic, is based on the use of mosfets as switches rather than as inverters. Pdf a new 5transistor xorxnor circuit based on the pass. Here the output of first xor gate is applied as a input to the next xor gate, second xor gate has c as second input and produce the sum as output. Logic gates digital circuit that either allows a signal to pass through it or not. Mar 03, 2014 pass transistor logic families complementary pass transistor logic family dual pass transistor logic family swing restored pass transistor logic family 31. Problem on nmos pass transistor logic gate 2014 ece paper solution duration. A hybrid cmos logic style adder with 22 transistors is reported 7. Conference paper pdf available december 2011 with 3,665 reads. Feb 27, 2017 problem on nmos pass transistor logic gate 2014 ece paper solution duration.
Pdf a differential double pass transistor logic unit. Pass transistor logic often uses fewer transistors, runs faster, and requires less power than the same function implemented with the same transistors in fully complementary cmos logic. Hello and welcome original pdf to todays lecture on pass transistor logic circuits this is the page replacement policies pdf second. Spl singlerail passtransistor logic is one of the most promising logic.
Some logical circuits using ptl pass transistor logic october 9, 2012 8 9. The xor gate realization of the circuit using six transistors can be found in 4 after modifying their four by transistors. And, or, not, nand not and, nor not or, xor, and xnor not xor later building functions. Then leap which is singlerail pass transistor logic then differential. Pass transistor is wellsuited to circuits that contain large proportions of xor gates and arithmetic units, because ptl based. It shows some fundamental pass transistor building blocks which became. Passtransistorlogic xor gate using pass transistor logic. The paper proposes the novel design of a 3t xor gate combining complementary cmos with pass transistor logic. Full adder design with 10 transistors using xorxnor gates is also reported in 6. A new 5transistor xorxnor circuit based on the pass transistor logic. The multiplexers in the design are based on the pass transistor logic ptl because these are simple to construct and occupies less chip area per component. Section 3 describes a general method to synthesize basic twoinput and threeinput logic gates andnand, ornor, and xor xnor in each of. Index terms adder circuits, cpl, complementary cmos, lowvoltage lowpower logic styles, passtransistor logic, vlsi circuit design.
Implement an xor gate using minimum number of transistors. Sizing the transistors in a cmos transmission gate. Pass transistor logic f product term control signal pass signal v p if 1. Differential and passtransistor cmos digital circuits. A general method in synthesis of passtransistor circuits people. Nikolic designing dpl gates a b 0 0 0 1 c 1 c 2 c 3 c 4 a a b a.
Cmpen 411 vlsi digital circuits spring 2012 lecture 07. This paper compares the use of complementary passtransistor logic cpl as more powerefficient than conventional cmos design. Section 3 describes a general method to synthesize basic twoinput and three input logic gates. Xor xnor ptl cell with 16 transistors is reported in 4.
Bdd decomposition for delay oriented pass transistor logic. The design has been compared with earlier proposed 4t and 6t xor gates and a significant improvement in silicon area and powerdelay product has been obtained. A novel 1bit full adder design using dcvsl xorxnor gate. Figure below shows the implementation of xor function using pass transistors. Used to build logic functions there are seven basic logic gates. The advantage of pass transistor logic is that it can be implemented using very less number of transistors, hence very less power dissipation. A general method in synthesis of passtransistor circuits. Slide set 3 pass transistor logic transmission gates. This paper compares the use of complementary pass transistor logic cpl as more powerefficient than conventional cmos design. 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. Cmos is the logic style of choice for the implementation of arbitrary combinational circuits if low voltage, low power, and small powerdelay products are of concern. The algorithm is used to synthesize basic logic gates andnand, ornor, and xorxnor in three conventional passtransistor techniques.
Logic circuits adapted from cmos logic circuit design by john p. Based on the study, an approach of designing multipleinput passtransistorlogic xor gates is proposed. One of the first papers examining passtransistor logic and formalizing passtransistor design style was published by whitaker, in 1983 whitaker, electronics. Section 3 describes a general method to synthesize basic twoinput and threeinput logic gates andnand, ornor, and xorxnor in each of. Alternatively, static pass transistor circuits have also been suggested for lowpower applications 2. A comparative performance analysis of various cmos design. A new 5transistor xorxnor circuit based on the pass transistor logic conference paper pdf available december 2011 with 3,665 reads how we measure reads.
Oct 09, 2012 pass transistor logic october 9, 2012 7 8. Vec i tno tn increases of pass transistor due to body effect v sb v gs. Index termssbinary decision diagrams bdds, pass transistor logic, logic synthesis, functional decomposition i. Clike languages use the caret symbol to denote bitwise xor. The truth table of xor gate is as shown in table below. Cmosbased carbon nanotube passtransistor logic integrated. For some types of functions, this can lead to much more efficient implementations than using gates.
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