DESIGN AND ANALYSIS OF UNIVERSAL 4-BIT BARREL SHIFTER USING LOW POWER MULTIPLEXERS

Abstract

This report highlights a comparative analysis of eight diverse techniques for 2×1 multiplexer. The functionality is similar but diversity achieved in terms of dynamic power consumption, delay and power delay product. Thereby enabling the designer to pick out the best fit technique for a specific application in keeping with their design requirement. The techniques that have been analysed are TG, GDI, PT, MSL, Static CMOS, CPL, CVSL and MTCMOS CVSL. For power application, GDI based multiplexer is the best suit as it reports minimum power consumption of 1.72 fW. While PT based technique has holistic power dissipation as the maximum and minimum power consumption is moderate at 198.53 nW and 0.2196 nW respectively. It also has least average power dissipation of 110.9 nW. If the timing plays a more crucial role for an application, then GDI is the fastest of all. It has the least input to output transmission time of 1.65 ps. While the power delay product is best for PT at 0.395 aJ. In terms of static power dissipation, the best performance is demonstrated by GDI based technique at 0.2199 nW. The multiplexers are designed at 90 nm technology node and simulated at supply voltage of 1 V. FinFET device is one of the most advance devices by which any logic circuit can be designed and will give better performance compare to MOSFET. Comparison is completed between MOSFET and FinFET based multiplexers and analysis of delay and power. Switching and scaling is also an important factor by which analyses of devices can be done. Switching of the signals causes the changes in the overall power dissipation. If signal is switching at same time instance power dissipation will be more and if switching at different time instance power dissipation will be less. Devices are getting smaller in size, using of same power supply will lead to more power consumption. Scaling of power supply will improve the overall performance of the device. MOSFET is analysed at 1V, 0.8V, 0.6V and FinFET is analysed at 0.8V, 0.6V, 0.4V. The designing and simulation are done using MOSFET at 90nm technology node and by using FinFET at 10 nm technology on cadence virtuoso. A comparison is made between FINFET based Gate Diffusion Input (GDI) and Pass Transistor (PT) based 2:1 Multiplexers in terms of delay, average power dissipation, and Power delay product (PDP). Both the multiplexers are designed using an 10nm technology node and functional at 0.8V supply voltage. GDI based mux consumes very less power dissipation of 839.3nW, which is 88.08% lesser than the PT based Mux. If the user requirement is of fast operation than GDI based Mux meets the criteria. It takes 0.0107ps to pass the signal at the

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output, which is 165.42 times faster than PT based Mux. PDP of GDI and PT based Mux is 0.00029aJ and 0.1aJ. Additionally, GDI based Mux demonstrates better performance with 3.15nW power dissipation. The multiplexers can be used in many combinational circuits, therefore, if the performance of the multiplexer is improved, the complete circuit is bound to give better performance. Finally, GDI and PT techniques are used to design barrel shifters for MOSFET as well as FinFET technology. Using FinFET based technology designing of barrel shifter is achieved, in both Barrel Shifter GDI based Barrel shifter shows the better performance, maximum power dissipation of GDI based barrel shifter is 468.5nW which is 13.85 times less than PT based barrel shifter. Whereas minimum power dissipation is 154.48nW. GDI based barrel shifter takes 47.27ps to pass the input to the output, it is 15.23ps less compare to PT based barrel shifter. Analysis states that GDI based Universal Barrel Shifter shows the better performance.