4-BIT CARRY LOOK AHEAD ADDER

1. 4-BIT CARRY LOOK AHEAD ADDER Jaime Cordoba Advisor: Dave Parent May 19, 2004

2. Agenda • Abstract • Introduction • Why • Simple Theory • Back Ground information (Lit Review) • Summary of Results • Project (Experimental) Details • Results • Cost Analysis • Conclusions

3. Abstract • I designed an 4-bit carry look ahead adder that operates at a frequency of 200 MHz and has a propagation delay of .5ns and occupies an area of 375 x 160mm^2

4. Introduction • Carry look ahead adders are important because they are building blocks for other logics such as MSI adders and ALUs. • The carry look ahead logic is the adder stage that generates a carry and propagates carry

5. Project Details • Hand Calculations • Cell based technique • Build each layout of gate seperately and performed an LVS • Final Schematic • Final Layout • Final Simulation

6. Longest Path Calculations Note: All widths are in microns and capacitances in fF

7. Schematic

8. Layout

9. Verification

10. Simulations

11. Cost Analysis • Time spent on each phase of project • verifying logic= 10 hours • verifying timing= 5 hours • Layout= 25 hours • post extracted timing= 5 hours

12. Lessons Learned • Do not procrastinate • Start as early as possible • Make a schedule and follow it • Talk to your instructor

13. Summary • My objective was to design a 4-bit carry look ahead adder with a propagation delay of .5ns • Carry adders are important and are implemented in ALUs and other logics

14. Acknowledgements • Thanks to my wife for putting up with me • Thanks to Cadence Design Systems for the VLSI lab • Thanks to Synopsys for Software donation • A million thanks to Professor Dr. Parent