Post on 17-Jan-2016
GROUP: 17NAME:SHAUN PRAKASH (1061107216)JAI PRAKASH (1061105253)RAJENDRAN (1061105607)
Integrated VLSI SystemsEEN4196
Title: 4-bit Parallel Full Adder
CONTENTS
Introduction Design Methodology Schematic Diagram Simulated Result Layout Conclusion
INTRODUCTION
4-bit Parallel Full Adder
INTRODUCTION
4-bit Parallel Full Adder Binary Addition and Operation
DESIGN METHODOLOGY
TRANSISTOR SIZING
In our full adder design, we are using the 0.35 µm CMOS technology. So the length of the transistor we fixed to 0.35 µm.
L = 0.35 µm
The default ratio of W to L
W/L = 3
So, we design the width of the NMOS 2.5 times its length
WN = 0.35 µm x 3 = 1.05 µm
As the width of the PMOS is 2 times the width of NMOS, hence
WP = 1.05 µm x 2 = 2.1 µm
SCHEMATIC DIAGRAM
Schematic Diagram of Full Adder
SCHEMATIC DIAGRAM
Schematic Diagram of 4-bit Parallel Full Adder
SIMULATION RESULT
Output for First Block
SIMULATION RESULT
Output for Second Block
SIMULATED RESULT
Output for Third Block
SIMULATED RESULT
Output for Fourth Block
SIMULATED RESULT
Power Dissipation
•As temperature increases, power dissipation increases
Temperature, oC Power Dissipation, W
0 3.7083m
27 5.0536m
95 12.081m
SIMULATED RESULT
Propagation Delay
Proportional As the temperature increases, the
propagation delay increases Due to degradation of carrier mobilities when the temperature is increased.
Temperature
(°C)
Rising edge delay
(ps)
Falling edge delay
(ps)
0 -13.232 -4.3647
95 27.8300 10.8075
LAYOUT
Layout of One Full-Adder Block
LAYOUT TECHNIQUE
Same transistor types are grouped together less complex design.
To reduce the total size occupied. reduce power consumption.
The rule of thumb technique reduce the collision between metal routings and to reduce the complexity during top-level design.
CONCLUSION
Transistor count: 112 (28 per full adder circuit)
Layout area: 163.4µm x 227.1µm Power dissipation (27 oC): 5.0536mW
CONCLUSION
In conclusion, the schematic designed in this project is acceptable, at which the performance and delay is under reasonable range. The design can be considered as successful, due to the adequate precision and low power consumption. Future improvement on the current design is possible to achieve higher performance.