Design of High-Speed Circuits 🚧
Factors to Consider in High-Speed PCB Design
- Cost control
- Layer stack-up principles
- Layout principles
- Routing principles
- Impedance design
- Signal integrity
- Power integrity
- EMC design
- Thermal design
- DFM design
Differences Between Two-Layer and Multilayer Boards
- Calculation of reference planes and impedance
- Shorter return paths in multilayer boards
- Easier routing
- Higher cost of multilayer boards
Layer Stack-up Guidelines
- Components and soldering surfaces should have complete ground planes (for shielding purposes)
- Avoid adjacent parallel routing layers as much as possible (to prevent interference)
- All signal layers should be adjacent to ground planes; critical signals should be adjacent to ground layers without crossing split planes (to minimize return paths)
Based on the above, the recommended layer stack-up scheme is:
- Top layer: Signal 1
- Inner layer 1: Ground
- Inner layer 2: Power
- Bottom layer: Signal 2
To reduce edge radiation, the power layer should be pulled back at least 1 mm from the ground layer.
PCB Impedance Design Requirements for Different Communication Protocols
| High-Speed Signal | Impedance Requirement | Tolerance | Routing |
|---|---|---|---|
| DDR | 100Ω | ±10% | |
| eMMC | 50Ω | ±10% | |
| PCIe | |||
| USB | 90Ω | ±10% | Differential |
| HDMI | 100Ω | ±10% | |
| eDP | 90Ω | ±10% | Differential |
| MIPI | 100Ω | ±10% | Differential |
| SDIO/SDMMC | 50Ω | ±10% |
Some Basic Concepts
- Signal Integrity: Signal integrity refers to the quality of a signal on a signal line. Good signal integrity means that the signal has the necessary voltage levels when needed.
- Transmission Line: A transmission line is a connection line composed of two conductors
References and Acknowledgements
- High-Speed Signal PCB Design
- Is High-Speed Circuit Design Difficult to Learn? Familiarize Yourself with These 48 Basic Concepts and You'll Get Started
Original: https://wiki-power.com/ This post is protected by CC BY-NC-SA 4.0 agreement, should be reproduced with attribution.
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