Digital Circuit Design

Circuit Design

• Involves designing and verifying digital circuits at the transistor level
• Involves creating a netlist, which is a circuit description in terms of components and their interconnections
• Types of circuit design:
  • Synchronous design: uses a clock signal to synchronize the operation of the circuit
  • Asynchronous design: does not use a clock signal, instead using handshaking protocols to coordinate operations
  • Analog circuit design: involves designing circuits that operate on continuous signals

Placement And Routing

• Placement: involves placing components (transistors, diodes, etc.) on the chip surface to optimize performance, power consumption, and area usage
• Routing: involves connecting the components using wires to form the desired circuit
• Placement and routing algorithms:
  • Simulated annealing: uses a probabilistic approach to find the optimal placement and routing
  • Force-directed placement: models the circuit as a system of forces and iteratively updates the placement to minimize energy
  • Steiner tree-based routing: uses a minimum spanning tree to connect the components

Semiconductor Manufacturing

• Involves fabricating the designed circuit on a semiconductor material (e.g. silicon)
• Steps in semiconductor manufacturing:
  1. Wafer preparation: growing and cutting the semiconductor material into wafers
  2. Layer formation: depositing and patterning layers of materials (e.g. insulators, conductors, semiconductors)
  3. Lithography: transferring the pattern onto the wafer using light and photoresist
  4. Etching: removing material to create the desired pattern
  5. Doping: introducing impurities to modify the electrical properties of the semiconductor
  6. Metallization: adding metal interconnects to connect the components

Logic Synthesis

• Involves converting a high-level description of the desired circuit behavior into a netlist
• Involves two main steps:
  1. Functional synthesis: converting the behavioral description into a register-transfer level (RTL) description
  2. Technology mapping: converting the RTL description into a netlist
• Logic synthesis techniques:
  • Two-level logic minimization: reducing the number of gates in the circuit
  • Multilevel logic synthesis: using a hierarchical approach to synthesize the circuit

Floorplanning

• Involves designing the overall architecture of the chip, including the placement of components and interconnects
• Involves optimizing the floorplan to minimize area, power consumption, and latency
• Floorplanning techniques:
  • Rectangular dualization: representing the chip as a rectangular dual graph to optimize the floorplan
  • Slicing tree-based floorplanning: using a slicing tree to represent the chip and optimize the floorplan

Circuit Design

• Designs digital circuits at the transistor level
• Creates a netlist, a circuit description of components and interconnections
• Three types of circuit design:
  • Synchronous design: uses a clock signal for synchronization
  • Asynchronous design: uses handshaking protocols for coordination
  • Analog circuit design: operates on continuous signals

Placement And Routing

• Placement: optimizes component placement on the chip surface
• Routing: connects components using wires to form the desired circuit
• Three placement and routing algorithms:
  • Simulated annealing: uses probabilistic approach for optimal placement and routing
  • Force-directed placement: models circuit as a system of forces to minimize energy
  • Steiner tree-based routing: uses minimum spanning tree for connections

Semiconductor Manufacturing

• Fabricates designed circuits on semiconductor materials like silicon
• Six steps in semiconductor manufacturing:
  • Wafer preparation: grows and cuts semiconductor material into wafers
  • Layer formation: deposits and patterns layers of materials
  • Lithography: transfers patterns onto the wafer using light and photoresist
  • Etching: removes material to create desired patterns
  • Doping: introduces impurities to modify electrical properties
  • Metallization: adds metal interconnects to connect components

Logic Synthesis

• Converts high-level descriptions into a netlist
• Two main steps:
  • Functional synthesis: converts behavioral description to RTL description
  • Technology mapping: converts RTL description to a netlist
• Two logic synthesis techniques:
  • Two-level logic minimization: reduces number of gates in the circuit
  • Multilevel logic synthesis: uses hierarchical approach to synthesize the circuit

Floorplanning

• Designs the overall chip architecture, including component placement and interconnects
• Optimizes floorplan to minimize area, power consumption, and latency
• Two floorplanning techniques:
  • Rectangular dualization: represents the chip as a rectangular dual graph
  • Slicing tree-based floorplanning: uses a slicing tree to represent the chip