When it comes to gold- vs. tin-plated contacts in HDMI connectors, is there really a difference in performance between the two? Over the past few months, we at DPL Labs have received numerous inquiries about the differences between the two.
The topic of gold- vs. tin-plated contacts has been heavily debated since the late 1960s. The conversations now play out much like the discussions around oxygen-free copper (OFC), which was marketed despite widespread uncertainty about its actual benefits.
Testing the Performance of Gold vs. Tin Contact Pins
Our test objective is to evaluate comparative longevity, electrical performance, and wear characteristics of HDMI connectors with gold and tin contacts under a controlled insertion/removal test. For this, two types of HDMI connectors were selected:
- Gold-Plated Contacts: 10-30µin (micro inches) of gold over a nickel barrier.
- Tin-Plated Contacts: Pure tin or tin-lead alloy over a copper base.
Test Equipment and Procedure
- Automated insertion test rig to maintain consistent insertion force and alignment.
- High-resolution optical and scanning electron microscope (SEM) for contact wear analysis.
- Multilane 400Gbps oscilloscope for eye pattern and jitter analysis.
- Micro-ohmmeter to track contact resistance changes.
Each sample was subjected to 1,000, 5,0000, and 10,0000 insertion/removal cycles. The test fixture ensured a solid control force and angle during insertion.
Contact Resistance Measurements were made at these intervals to detect increases indicating contact distortion or degradation.
Visual wear inspections were implemented throughout each connector’s test analyzing contact surface wear and distortions.
Finally, signal integrity testing was introduced using a 10Gpbs signal on each contact. Eye Pattern analysis was performed to track any changes. The results were fascinating, to say the least
Gold vs. Tin Plating Test Results
Mechanical Wear and Degradation
- Gold-Plated Contacts: Minimal wear observed up to 10,000 cycles, with surface retention of gold plating.
- Tin-Plated Contacts: Noticeable material wear after 5,000 cycles, with increased friction leading to material transfer and fretting corrosion.
Contact Resistance
- Gold-Plated Contacts: Resistance remained stable with only a minor increase past 10,000 cycles.
- Tin-Plated Contacts: Resistance increased significantly after 5,000 cycles, indicating oxidation and degradation of the contact surface.
Signal Integrity
- Gold-Plated Contacts: Maintained a stable HDMI signal with minimal jitter.
- Tin-Plated Contacts: Increased jitter and slight signal degradation after 5,000 cycles, more pronounced after 10,000 cycles.
Is a Tin or Gold Contact Finish Better?
Our study confirmed that gold-plated HDMI connectors provide superior durability, electrical reliability, and signal stability compared to tin-plated connectors. Gold plating resists oxidation, minimizing contact degradation and ensuring a more stable connection, making it the preferred choice for high-performance and high-cycle applications. In contrast, tin-plated contacts degrade more quickly due to oxidation and mechanical wear, making them less suitable for frequent plug-and-unplug scenarios.
Where Gold Contacts are Better than Tin
While consumer HDMI connectors may not typically experience extreme insertion cycles like this, the study highlights the long-term advantages of gold plating for a more reliable connection and unquestionable signal integrity. Gold-plated HDMI connectors are ideal for high-end consumer AV setups, gaming consoles, and environments requiring frequent connections.
When Tin Contacts Might Be Better Over Gold
Tin-plated HDMI connectors can be a cost-effective option for low-cycle applications where signal integrity demands are lower.
