Digital Circuit Design

Study Notes

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: 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

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

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

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

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: 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

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

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