ROUTING - GROUP 4

Introduction to PCB Routing

PCB routing involves creating electrical connections between components, pads, and traces on a printed circuit board (PCB).

PCB Routing Tools: Software applications used for designing electrical connections on PCBs.
- Key Features:
  - Trace Placement
  - Via Placement
  - Design Rule Checking (DRC)
  - Electrical Rule Checking (ERC)
  - Signal Integrity Analysis
  - Thermal Analysis
  - Manufacturing Verification

Trace Placement: Automatically/manual placement of traces between components based on design rules.
Via Placement: Identifying optimal locations for vias, which connect traces across different layers.
Design Rule Checking (DRC): Ensuring the design adheres to specifications for trace width, spacing, and other parameters.
Electrical Rule Checking (ERC): Validating correct electrical connections to prevent short or open circuits.
Signal Integrity Analysis: Simulating high-speed signals to identify issues like crosstalk and impedance mismatches.
Thermal Analysis: Evaluating heat generated by components to prevent overheating.
Manufacturing Verification: Checking design manufacturability, ensuring traces and vias can be reliably processed.

Manual Routing: Involves manual placement and connection of tracks, suitable for precise designs but time-consuming.
- Tools: Design capture software and manual routing tools.
Automatic Routing: Software algorithms automatically connect components based on design rules.
- Features: Includes rip-up and re-route, shape optimization, congestion avoidance, DRC.

Advantages: Precision, flexibility, control.
Disadvantages: Time-consuming, less control, error-prone in complex designs.

Advantages: Speed, efficiency, consistency.
Disadvantages: Less control over final routes, can struggle with complex layouts.

KiCad: Open-source, comprehensive suite for designing electronic circuits.
Autodesk Eagle: User-friendly, good for beginners with a free version.
EasyEDA: Cloud-based, accessible from any device with integration to manufacturing services.
Fritzing: Good for hobbyists with a focus on educational use.

Through-hole Via: Extends through the entire board to connect layers.
Blind Via: Connects outer to inner layers without going through the entire thickness.
Buried Via: Connects two inner layers, not visible from the outer surface.
Via-in-Pad: Directly under a component pad for improved signal quality.
Micro Via: Smaller vias for high-density designs.
Via Tenting: Covers via with a non-conductive material to prevent contamination.

Electrical Connections: Act as bridges between PCB layers; performance can be influenced by various factors, like length and diameter.
Signal Integrity: Vias can affect propagation delay and noise but can help manage grounding and shielding.
Thermal Management: Act as heat sinks, important for dissipating heat from components.

Signal Loss: Resistance, skin effect, and impedance mismatch can introduce losses.
Capacitance: Vias can create parasitic capacitance affecting high-frequency response.
Inductance: Related to via placement and can lead to delays and noise issues.

Trace Clearance: Prevents shorts and maintains signal integrity.
Pad Clearance: Prevents solder bridges between component pads, crucial for reliability.
IPC 2221 Standards: Specifies minimum spacing between conductors based on voltage.
Factors Affecting Clearance: Signal frequency, trace width, component size, and manufacturing tolerances.