Card edge connectors - contacts are electrical components that enable printed circuit boards (PCBs) to connect directly to other circuits or devices through their edges. These connectors utilize conductive pads or gold fingers on the PCB edge as contact points, eliminating the need for separate cable assemblies. They are critical in modular electronics design, offering space efficiency, high reliability, and ease of maintenance. Their importance spans computing, telecommunications, industrial automation, and consumer electronics sectors.
| Type | Functional Features | Application Examples |
|---|---|---|
| Double-Ended Edge Connectors | Two mating interfaces for daisy-chaining PCBs | Server backplanes, industrial control systems |
| Single-Ended Edge Connectors | Direct PCB-to-cable connection | Graphics cards, storage modules |
| High-Density Edge Connectors | Sub-1mm contact pitch with >100 circuits | Telecom routers, AI accelerators |
| Low-Profile Edge Connectors | 5mm height for compact devices | Smartphones, tablets |
Typical construction includes: - Contact area with phosphor bronze or beryllium copper terminals (gold-plated for corrosion resistance) - Insulating body using LCP or PBT thermoplastic materials - Polarization keying to prevent misalignment - Mechanical retention features (latches or screws) - EMI shielding contacts in high-speed variants
| Parameter | Typical Range | Importance |
|---|---|---|
| Contact Resistance | 5-20 m | Affects signal integrity |
| Current Rating | 1-5A per contact | Determines power handling |
| Insulation Resistance | >1 G | Ensures electrical safety |
| Operating Temperature | -55 C to +125 C | Environmental reliability |
| Mating Cycles | 100-10,000 cycles | Lifespan prediction |
| Manufacturer | Representative Product | Key Features |
|---|---|---|
| Amphenol ICC | EdgeCard 2.0 | 0.8mm pitch, 3,000V dielectric withstand |
| Molex | SL Series | Self-aligning contacts, 10Gbps capability |
| TE Connectivity | Edge D-Grid | Modular design, RoHS compliant |
| Samtec | Edge Rate | 1.27mm pitch, 12.5Gbps differential pairs |
Key considerations: - Required current/voltage ratings with safety margins - Environmental factors (temperature, vibration) - Signal speed requirements (for high-speed digital applications) - Mechanical constraints (board space, insertion force) - Cost-volume trade-offs for production scale
Emerging developments include: - Migration to 0.4mm pitch connectors for mobile devices - Integration of coaxial contacts for 56Gbps+ serial links - Adoption of lead-free surface finishes (ENIG, immersion tin) - Development of hybrid optical-electrical edge interfaces - Increased use of simulation tools for contact reliability prediction