1 4 BIT Arithmatic and Logic Unit (Fairchild DM74LS181) Kunjal Shah Radha Dharmana Rutu Pandya Vennela Patchala. Advisor: Dr. David, Parent December 5, 2005

2 Agenda Abstract Introduction –Why –Simple Theory –Back Ground information (Lit Review) Design Flow Project (Experimental) Details Results Cost Analysis Lessons Learned Acknowledgement

3 Abstract Specifications of ALU Load : 25 fF 16 arithmathic functions 16 logical functions Propagation delay : 5ns Clock frequency : 200 MHz Power requirement : 17 mW Occupied Area : 373 x373um

4 Introduction Why? The Arithmatic and Logic Unit is a building block of several industrial circuits. Design consists of different kinds of Arithmatic operations like Ripple carry adder, subtractor, Transfer data.. Logical operations like AND, OR, XOR, INV. How the ALU is designed and how it works is essential for designing advanced circuits.

5 ALU Block Diagram

6 Design flow

7 Longest path

8 Longest path calculations

9 Schematic

10 Logical Operations

11 Arithmetic Operations

12 Layout

13 DRC Verification

14 Transient Response A=0, B=1, M=1, S=E, F0 =1, F1=F2 = F3 = 0, F =A+B

15 Power

16 Cost Analysis Time spent on each phase of the project –Verifying logic 1 week –Logic reduction 1 week –Transistor sizing 1 week –Layout of individual blocks 2weeks –Integration of blocks 3 days –post extracted timing 1 day

17 Lessons Learned The circuit can be used as a building block for 16/32-bit ALU. Same metal should not be used in both horizontal and vertical direction.

18 Acknowledgement Thanks to Cadence Design Systems for the VLSI lab Thanks to Professor David W. Parent for his guidance.