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 2011 lecture 07. The advantage of pass transistor logic is that it can be implemented using very less number of transistors, hence very less power dissipation. A transistor is an electronic device that has three ends.
A comparative performance analysis of various cmos design. Pdf a new 5transistor xorxnor circuit based on the. The result is in some cases conceptual simplification, but the cmos inverters strict logichighlogiclow output characteristic is lost. Pdf a high speed 8 transistor full adder design using. 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. 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. Full adder design with 10 transistors using xor xnor gates is also reported in 6. One of the first papers examining passtransistor logic and formalizing passtransistor design style was published by whitaker, in 1983 whitaker, electronics. Pass transistor logic f product term control signal pass signal v p if 1. Vec i tno tn increases of pass transistor due to body effect v sb v gs.
Xor has the worstcase karnaugh mapif implemented from simple gates, it requires more transistors than any other function. Two transistor xor gate based single bitfull adder design. Introduction conventional static cmos has been a technique of choice in most processor design 1. 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.
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. Passtransistor logic switch network a b b reduced number of transistors. 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. Lower noise margin is the disadvantage of pass transistor logic. Pdf dualthreshold passtransistor logic design researchgate. Pass transistor logic has been considered a low power logic 14,15. 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. Bdd decomposition for delay oriented pass transistor logic. And, or, not, nand not and, nor not or, xor, and xnor not xor later building functions. The main motive of this paper is to determine the comparative study of power, delay. Minimum operating voltage of logic gates in 65nm cmos, ieee, november, 2011, pp 2126. The operation of a transistor could be explained by making an analogy to faucets. Cmosbased carbon nanotube passtransistor logic integrated. Comparison of equivalent resistance for cpl, cmos, and.
The implemented functions are arithmetic, xor and mux based circuits. Xor gate is wildly used in half adder, subtractor and multiplier. Pnp transistors as commonemitter switches duration. Introduction to passtransistor logic technical articles. 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. This analysis results in the modified karnaugh map, which indicates that b is the control variable, and a and c are the pass variables, resulting in the transmissiongate based and the passtransistor based implementations shown in figure 2. Mar 03, 2014 pass transistor logic families complementary pass transistor logic family dual pass transistor logic family swing restored pass transistor logic family 31. Some logical circuits using ptl pass transistor logic october 9, 2012 8 9. Implement an xor gate using minimum number of transistors. Design of high performance multipleinput passtransistor. Transistor transistor logic ttl family one basic function of ttl ic is as a complimenting switch or inverter. Transmission gate an overview sciencedirect topics. Then leap which is singlerail pass transistor logic then differential.
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. Topology of 2 input subnanowatt xor gate in 65nm cmos. A novel 1bit full adder design using dcvsl xorxnor gate and. In 2 a 16 transistors full adder cell with xorxnor, pass transistor logic ptl and transmission gate is reported. Comparative performance analysis of xorxnor function based. Logic gates a b out 0 0 0 0 1 1 1 0 1 1 1 1 a b out 0 0 0 0 1 0 1 0 0.
Passtransistorlogic xor gate using pass transistor logic. Note that the caret does not denote logical conjunction and in these languages, despite the similarity of symbol. He was born in lincoln, england and he was the son of a shoemaker. In this lecture, we will talk about another way to implement logic functions using transistors.
Problems design 4 to 1 multiplexor using transmissiongates. Pdf this paper introduces passtransistor logic design with dualthreshold voltages. Abstractpasstransistor logic ptl uses pass transistors to directly pass logic. Index terms adder circuits, cpl, complementary cmos, lowvoltage lowpower logic styles, pass. Logic gates digital circuit that either allows a signal to pass through it or not. Full adder design with 10 transistors using xorxnor gates is also reported in 6. Section 3 describes a general method to synthesize basic twoinput and threeinput logic gates andnand, ornor, and xorxnor in each of. Index terms adder circuits, cpl, complementary cmos, lowvoltage lowpower logic styles, passtransistor logic, vlsi circuit design. The paper proposes the novel design of a 3t xor gate combining complementary cmos with pass transistor logic.
Differential and passtransistor cmos digital circuits. Comparative performance analysis of xorxnor function based highspeed cmos full. Andnand, ornor, and xorxnor in each of these families. Passtransistor logic ptl, also known as transmissiongate logic, is based on the use of mosfets as switches rather than as inverters. Spl singlerail passtransistor logic is one of the most promising logic.
If the faucet knob gate is turned on water flows from the source to the sink, otherwise if the faucet. Complementary passtransistor logic cpl with 32 transistors having high power dissipation and better driving capability is reported in 4. Simple xor makes it attractive for structures like adders. Pdf a differential double pass transistor logic unit. 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. Based on the study, an approach of designing multipleinput passtransistorlogic xor gates is proposed. The current drive of the transistor gatetosource voltage is reduce significantly as v. Oct 09, 2012 pass transistor logic october 9, 2012 7 8. Logic circuits adapted from cmos logic circuit design by john p.
Figure below shows the implementation of xor function using pass transistors. Digital integrated circuits combinational logic prentice hall 1995 overview static cmos conventional static cmos logic ratioed logic pass transistortransmission. 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. A new 5transistor xorxnor circuit based on the pass transistor logic. Used to build logic functions there are seven basic logic gates. The paper describes how the logic functions can be efficiently and optimally built using passtransistor logic. Clike languages use the caret symbol to denote bitwise xor.
The hybrid adder is designed using dcvsl gates because these can produce both complementary and true outputs using single gate architecture. 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. For low power applications pass transistor logic ptl is best suitable technique and explanation was given in. 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. Section 2 gives an overview of three conventional passtransistor logic families complementary passtransistor logic cpl, double passtransistor logic dpl, and dual value logic dvl. Indeed, designing highspeed lowpower circuits with. Problem on nmos pass transistor logic gate 2014 ece paper solution duration. Vlsi design pass transistor logicpass transistor logic. A novel 1bit full adder design using dcvsl xorxnor gate. Realizing constructing a cmos pass gate cmos transmission gate from transistors. A general method in synthesis of passtransistor circuits people. Conference paper pdf available december 2011 with 3,665 reads. This paper compares the use of complementary passtransistor logic cpl as more powerefficient than conventional cmos design.
Single bit full adder design using 8 transistors with. The advantage of pass transistor logic ptl is that. Xor xnor ptl cell with 16 transistors is reported in 4. The truth table of xor gate is as shown in table below. Pdf a new 5transistor xorxnor circuit based on the pass. Logic gates digital circuit that either allows signal to pass through it or not used to build logic functions seven basic logic gates. The algorithm is used to synthesize basic logic gates andnand, ornor, and xorxnor in three conventional passtransistor techniques. Passtransistor logic switch network a b b reduced number of transistors no static power consumption. V s will initially charge up quickly, but the tail end of the transient is slow. Feb 27, 2017 problem on nmos pass transistor logic gate 2014 ece paper solution duration. Cmpen 411 vlsi digital circuits spring 2012 lecture 07. Alternatively, static pass transistor circuits have also been suggested for lowpower applications 2. And, or, not, nandnot and, nornot or, xor xnornot xor 9 did you know. The xor gate realization of the circuit using six transistors can be found in 4 after modifying their four by transistors.
Logic network employs input signals at both gate and drain terminals. Section 3 describes a general method to synthesize basic twoinput and threeinput logic gates andnand, ornor, and xor xnor in each of. Vlsi design pass transistor logicpass transistor logic adapted from rabaeys digital integrated circuits, 2002, j. Pass transistor logic adapted from rabaeys digital integrated circuits, second edition, 2003 j.
Here the output of first xor gate is applied as a input to the next xor gate, second xor gate has c. Section 3 describes a general method to synthesize basic twoinput and three input logic gates. Index termssbinary decision diagrams bdds, pass transistor logic, logic synthesis, functional decomposition i. Comparative performance analysis of xorxnor function. Sep 17, 2016 realizing constructing a cmos pass gate cmos transmission gate from transistors. Slide set 3 pass transistor logic transmission gates. Hello and welcome original pdf to todays lecture on pass transistor logic circuits this is the page replacement policies pdf second. An eight transistor full adder has been designed using the proposed threetransistor xor gate and its performance has. Xorxnor ptl cell with 16 transistors is reported in 4. 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. Readers are encouraged to try implementing other boolean functions with this approach.
A general method in synthesis of passtransistor circuits. Design of efficient passtransistor binary alu asee. Sizing the transistors in a cmos transmission gate. A hybrid cmos logic style adder with 22 transistors is reported 7. Pass transistor logic xor gate using 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. For some types of functions, this can lead to much more efficient implementations than using gates. This paper compares the use of complementary pass transistor logic cpl as more powerefficient than conventional cmos design.1386 177 770 1037 230 1339 417 27 708 159 731 944 1614 181 1372 248 94 198 394 1324 476 975 798 798 212 114 1608 918 611 1484 189 806 1194 239 922 1102