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DESIGN OF 8-BIT ALU. Vijigish Lella Harish Gogineni Bangar Raju Singaraju Advisor: Dr. David W. Parent 8 May 2006. Agenda. Abstract Introduction Summary of Results Project (Experimental) Details Results Conclusions. Abstract. The Aim of the project is to design a 8-bit ALU.
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DESIGN OF 8-BIT ALU Vijigish Lella Harish Gogineni Bangar Raju Singaraju Advisor: Dr. David W. Parent 8 May 2006
Agenda • Abstract • Introduction • Summary of Results • Project (Experimental) Details • Results • Conclusions
Abstract • The Aim of the project is to design a 8-bit ALU. • The circuit is designed so as to meet the following specifications: • Frequency: 200 MHz. • Power : 100 mW. • Area : 576x840 µm2 • The design was done in AMI06 technology using Cadence tools.
Introduction Why this project? • The ALU is a fundamental building block of any computing system. • Challenging to design a 18 logic level design using CMOS Technology. • Design consists of different kinds of logic… Brent-Kung Adder, DFF, AOI3333, Mux, Inv, Nand, Nor, Xor, etc.
Design Flow Gate level Design Functional Table Schematic of Individual cells Calculations for the Critical Path NC Verilog Verification Layout of Individual cells DRC & LVS for each bit Integration of bits Final DRC & LVS
Project Summary • The ALU performs 1 Arithmetic function and 9 Logical functions at 200MHz. • Uses Brent Kung Adder to perform addition. • Design uses maximum power of 100mW • Maximum area is 576 x 840µm2
Propagate Generate C1 C2 C3 C4 C5 C6 C7 C8 ADD AxorB AB A+B AINV NAND BINV OR NOR M XNOR
Longest Path Calculations GATE C int Cg Tphl Nsn Nsp N M R Wn Wp F F s cm cm Total Propagation delay for the longest path = 3.72ns
Layout OUTPUT DFF INPUT
Results • The ALU performs all 10 functions at a 200MHz clock and a load of 20fF. • Area of the layout is 576 x 840µm2
Conclusions • Designed a 8-Bit ALU that performs arithmetic and logical functions at 200MHz frequency driving up to 20fF. • The Logic design can be modified to perform more functions.
Lessons Learned • Cell based design • Uniform cell height • Floor planning • Grid pattern for Vdd and gnd • Debugging LVS errors using extracted view
Acknowledgements • Thanks to Professor David W. Parent for his guidance. • Thanks to Cadence Design Systems for the VLSI lab