Livoa LogoLivoa


PROPOSAL: High-Speed Carry Look-Ahead Decimal Adder CLDA using CMOS Technology
Specification & Requirements • Operand Size e.g., 16- digit BCD • Target Frequency • Power Constraints

Algorithm Selection & Mathematical Modeling • Decimal Addition Algorithm • Carry Generation & Propagation Conditions • Pre-computation Formulae for Digit-Carry

High Level Architectural Design • Partition into Digit Slices 0 to n-1 • Define Carry Look-Ahead Network CLA • Define Correction Logic Block

Generate & Propagate Logic Design G_i and P_i for decimal digits considering BCD correction

Phase 2: CMOS Circuit Hierarchical Block Design
Digit Slice Design • 4-bit Binary Adder • Correction Logic Circuitry • Local Generate/Propagate
Carry Look-Ahead Network CLA • Multi-Level CLA Architecture • High-Fan-in Gate Design • Fast Carry Generation Circuitry

Transistor-Level Design • Choose CMOS Logic Family static, dynamic • Design Basic Gates NAND, NOR, XOR • Optimize for speed & area

Transistor Sizing & Optimization • Logical Effort Analysis • Size transistors for critical path • Buffer insertion for high fan-out nets
Phase 3: Pre-Layout Simulation & Validation
Test Bench Development • Generate exhaustive/random test vectors • Include corner cases
Functional Simulation • Verify logic correctness • Check BCD output & carry chain
Timing Analysis & Performance Characterization • Extract Netlist Parasitics • Measure Critical Path Delay T_cpd • Calculate Max Operating Frequency F_max
Proceed to Layout
Phase 4: Physical Design Layout & DRC
Layout/Design Iteration

Design Rule Check DRC • Verify layout against PDK rules • min width, spacing, enclosure

Layout vs Schematic LVS • Ensure layout matches schematic netlist

Parasitic Extraction • Generate Standard Parasitic Exchange Format SPEF • Extract R, C of Interconnects

Post-Layout Netlist Generation
Phase 5: Post-Layout Verification & Tape-Out

Post-Layout Simulation • Back-annotate parasitics into netlist • Re-run timing & power analysis with accurate wire delays

Final Performance Metrics • Final F max, Power, Area, PDP • Power-Delay Product
Tape-Out Preparation • Generate GDSII Stream File • Prepare for fabrication
Design Iteration


Meet all Specifications with Margin?

Power Analysis
Average Power Consumption
Static vs Dynamic Power Breakdown

Timing Analysis & Performance Characterization • Extract Netlist Parasitics • Measure Critical Path Delay T_cpd • Calculate Max Operating Frequency F_max

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by Pranav

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