PCB Traces
PCB traces are the conductive pathways on a printed circuit board (PCB) that connect electronic components. Its design, materials, and manufacturing processes directly impact the circuit's performance. PCB traces can also be widely used in membrane switch circuits, providing better back support and low contact resistance.
Key Features
|
Feature |
Description |
|
Substrate Material |
Common materials include FR-4 (glass-reinforced epoxy laminate), high-frequency PCB materials like Rogers and PTFE, and flexible substrates such as polyimide (PI). |
|
Conductive Layer |
Typically made of copper foil (electro-deposited or rolled-annealed), with thicknesses ranging from 0.5oz to 3oz (18µm to 105µm). |
|
Trace Width/Spacing |
Typically designed with a width and spacing of at least 0.1mm. High-density interconnect (HDI) boards can have traces as fine as 0.05mm or even smaller. |
|
Impedance Control |
For high-frequency signals, the trace width, dielectric thickness, and dielectric constant must be precisely calculated to achieve a specific impedance (e.g., 50Ω single-ended lines or 100Ω differential pairs). |
|
Surface Finish |
Various finishes are applied to protect the copper and ensure solderability: ENIG (Electroless Nickel Immersion Gold), HASL (Hot Air Solder Leveling), OSP (Organic Solderability Preservative), and Hard Gold Plating (for wear resistance). |
