2 to 1 multiplexer using nmos transistors pdf

Transmission gate an overview sciencedirect topics. Cmos design of area and power efficient multiplexer using. To illustrate this, consider the examples shown in figure 6. The power is optimized and explored using the multiplexer. Finally a 16 bit arithmetic logic unit is designed using mixed logic families such as cmos for basic logic functions, pseudo nmos for and logic and pass transistor logic for multiplexers, in order. The threshold voltage of both passtransistors of single unit of 2. Ece 410 homework 2 solution spring 2008 problem 1 using the rules given in lecture notes, find vg2 and vo required for both transistors to be on in the twotransistor circuit shown below. Latest cmos technology 45 nanometre library has been used in cadence virtuoso tool simulations. In terms of pure logic functionality, these are interchangeablethey both pass or block an input signal based on the state of a control signal. I am using pmos and nmos to implement complement a, means that i am not using complement directly into the circuit. Pdf this paper compares the use of complementary passtransistor logic cpl as more powerefficient than conventional cmos design.

So it would be a total of 8 gates times 2 for the amount of transistors, this would be 16 total transistors correct. Performance analysis of multiplexer using low power techniques indian j. The field of electronics is trending with miniaturization and reduction in the threshold voltage. Characteristics of a mos transistor using this model are shown in. Combining them we get a good 0 and a good 1 passed in both directions. Conclusion gate diffusion input gdi technique is used for implementing 2. Should i use nmos or pmos in cmos demultiplexer circuit. L14 combinational logic building blocks and bus structure. Lecture 2 circuits and layout university of pittsburgh. Common n well requires single supply to the circuit and reduces the power consumption in the 2 to 1 multiplexer circuit. So the number of cmos transistors are 206 transistors. From what i understand from another thread is if its implemented into a cmos i would need 1 pmos transistor and 1 nmos transistor so 2 transistors per 1 gate.

Pass transistor multiplexers can be built using transmission gates or the lone nmos type of switch. In this logic, we use 10 nmos transistors and 2 pmos transistors. Later the design flexibility and other advantages of the cmos were realized, cmos technology then replaced nmos at all level of integration. Nmos transistors are connected together for strong output. Vlsi1 class notes signal strength strengthof signal how close it approximates ideal voltage source vddand gnd rails are strongest 1 and 0 nmos pass strong 0 but degraded or weak 1 pmos pass strong 1 but degraded or weak 0 thus nmos are best for pulldown network 91118 page 15. Recall that nmos transistors are good at passing 0 and pmos transistors are good at passing 1, so the parallel combination of the two passes both values well. As we only have one control line, a then we can only switch 2 1 inputs and in this simple example, the 2 input multiplexer connects one of two 1 bit sources to a common output, producing a 2 to 1 line multiplexer. A multiplexer of 2 n inputs has n selected lines, are used to select. You will then have what is commonly known as time division multiplexing or tdm for short. 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. Whats the minimum number of transistors we can use to. Vddand gnd rails are strongest 1 and 0 nmos pass strong 0 but degraded or weak 1 pmos pass strong 1. The cmos transmission gate logic tgl is used to design a new 4. Nand gates are composed 160 pmos and nmos transistors, 16 inputs of nand gates are composed from 32 pmos and nmos transistor, and a cascade inverter is composed from four pmos and nmos transistors.

Thus this paper analyzes 2 to1 multiplexer using complementary cmos, dynamic and passtransistor logic styles. Instead of a dc input, we use a sinusoidal input as power clock pck input. Efficient layout design and simulation of cmos multiplexer by using different technologies. When i used muxes as shown in the diagram, my book said that i will be using 16 transistors. In nmos logic six nmos transistors are used to design 4. Convert the 2to1 mux without enable to a time division multiplexer tdm replace the slide switch select input s with a pulse module. A transmission gate tg is a complementary cmos switch. By contrast, conventional cmos logic switches transistors so the output.

The multiplexer has been realized with stacking power gating leakage reduction technique in 45 nanometer technology 10 11. Sep 17, 2016 cmos pass gate, transmission gate, wl ratio, on resistance. A multiplexer or mux is a combinational circuits that selects several analog or digital input signals and forwards the selected input into a single output line. An nmos switch is on when the controlling signal is high and is off when the controlling signal is low. A report on 2 to 1 mux using tg linkedin slideshare. When i used the nand, or, and not gates, i got 48 transistors. Examples of solved problems for chapter3,5,6,7,and8. The pdn is constructed using nmos devices, while pmos transistors are used in the pun. The input a of this simple 21 line multiplexer circuit constructed from standard nand gates acts to control which input i 0 or i 1 gets passed to the output at q from the truth table above, we can see that when the data select input, a is low at logic 0, input i 1 passes its data through the nand gate multiplexer circuit to the output, while input i 0 is blocked. Cmos pass gate, transmission gate, wl ratio, on resistance. Figure 1b shows the cmos transistor schematic configuration of 16 to 1 multiplexer.

This is the adiabatic diode discharge logic addl which consumes very less power as compared to pfal logic. Key word multiplexer, leakage power, nmos, pmos and transistor gating technique source voltage. Transistors are used as switches to pass logic levels between. Figure 6 2to1 multiplexer realized using a nmos pass transistors only, b using cmos transmission gates, c platch inverter, d aspect ratio of.

Cmos design of area and power efficient multiplexer using tree topology. Efficient layout design and simulation of cmos multiplexer by. All functions are implemented using nmos only, and pmos transistors serve only as the pullup devices. Solved how many transistors do i need to design a cmos xor. Design the 2x1 mux with 2t logic and comparing the. Metal oxide semiconductor field effect transistors nmos and pmos mosfets voltage applied to insulated gate controls current between source and drain low power allows very high integration. Low power multiplexer design using modified dcvsl logic. Realizing constructing a cmos pass gate cmos transmission gate from transistors. Multiplexer is a circuit in which n select lines select one of input lines and. Highperformance multiplexerbased logic synthesis using. The design of proposed 16to1 multiplexer has been nmos. Based on tgl, it removes the degraded output, the nmos and pmos are combined together for strong output level with the gain in area, which is a central result of proposed mux. I have a circuit using 3 not gates, 4 and gates, and 1 or gate.

Whats the minimum number of transistors we can use to build. Theprimary eason for this choice is that nmos transistors producer strong zeros, and pmos devices generate strong ones. Implementation of low power cmos full adders using pass. On the other hand, c0, places both transistors in cutoff, creating an open circuit between nodes a and b. The small transistor size and low power dissipation of cmos. When c1, both mosfets are on, allowing the signal to pass through the gate. Design of mux using different logic styles a logic style is the way how a logic function is implemented using a set of transistors. This design uses seven pv gates producing 14 garbage outputs.

The aim of this experiment is to design and plot the characteristics of a 4x1 digital multiplexer using pass transistor and transmission gate logic introduction. Sep 29, 2012 i have a circuit using 3 not gates, 4 and gates, and 1 or gate. Assume that only the uncomplemented inputs w1, w2, w3,andw4 are available. Adiabatic diode discharge logic based nibble multiplexer. This paper shows the contrast between conventional mux and mux using nmos transistors and accentuates the advantages of the latter. When control signal c is logic low the output is equal to the input a and when control signal c is logic high the output is equal to the input b. Solved how many transistors do i need to design a cmos. Pass transistor logic ptl describes several designs of circuits. Sizing the transistors in a cmos transmission gate. We can confirm this in the following boolean expression. Implementing multiplexers with passtransistor logic. At times, designers find it convenient to use an ideal switch that can pass both 0 and 1 well. While accurate modeling of the output conductance is essential for linear design, the. Instead of connecting the sources of nmos and pmos to ground and vdd respectively as for the inverter, we.