Design Solutions for USB, HDMI, and RJ45 Signal Integrity

1. Background and Design Challenges

   In high-speed communication interfaces such as USB, HDMI, and RJ45, electrostatic discharge (ESD) events are one of the most critical reliability threats.

   According to IEC 61000-4-2, discharge peaks can reach ±8kV (contact) and ±15kV (air).

   Without proper protection, transient surges can instantly damage the interface ICs, cause data errors, or shorten product lifespan.

2. Key Design Objectives

   The ideal ESD protection solution must achieve low capacitance, fast response, and low clamping voltage — protecting multiple lines while maintaining signal quality across data rates from 480Mbps (USB2.0) to 10Gbps (USB3.1, HDMI2.1).

3. JARON ESD Protection Portfolio

JARON offers a complete portfolio of ESD protection products designed for high-speed signal lines, covering single-channel, dual-channel, and quad-channel array structures.

JARON’s ESD portfolio offers ultra-low capacitance (as low as 0.3pF) and sub-nanosecond response time, suitable for USB3.1, HDMI2.1, and Gigabit Ethernet protection.

4. Design Principles for High-Speed Interfaces

Maintain Signal Integrity

   Ensure that ESD devices with capacitance ≤ 0.5pF are used, and maintain consistent differential impedance across traces to avoid reflection and signal distortion.

Minimize Return Path

   Place ESD protection close to the connector (<5mm distance) and ensure multiple ground vias for fast discharge return paths.

Layout and Symmetry

   Symmetrical placement and length matching in differential pairs preserve timing accuracy and reduce jitter in high-speed links.

5. Validation and Test Results

Test Conditions:

   ESD Test Standard: IEC 61000-4-2 ±8kV Contact Discharge

   Signal Rate: 10Gbps (HDMI 2.1)

   Equipment: JARON ESD3V3D5U (SOD-923)

With JARON ESD arrays, residual voltage dropped from 54V to 12V, jitter reduced by 71%, and bit error rate improved by 1,000,000× — confirming superior ESD performance with full signal preservation.

6. Application Examples

USB Type-C High-Speed ​​Interface

   Utilizes JARON ESD9L5V0ST for four-channel common-mode protection;

   Withstands ±15kV air discharge;

   Signal bandwidth supports up to 10Gbps.

HDMI 2.1 Video Interface

   Utilizes ESD3V3D5U array;

   Capacitors are only 0.3pF, not affecting TMDS differential signals;

   EMI noise reduction of 16dB.

RJ45 Ethernet Interface

   Utilizes ESD5V0D3B;

   Bidirectional protection structure, compatible with PoE systems;

   Suppresses lightning strikes and electrostatic surges.

7. Selection Reference Table

8. Standards and Compatibility

All JARON ESD components meet international standards, including IEC 61000-4-2 and JEDEC A114, ensuring compatibility with global OEM qualification processes.

9. Engineering Value and Design Benefits

JARON’s ultra-low-capacitance ESD devices deliver high-speed integrity with robust ±15kV protection — minimizing space, cost, and validation time.

10. Conclusion

   In high-speed data transmission interfaces, traditional ESD diodes can no longer simultaneously provide protection and signal integrity.

   JARON's ultra-low capacitance ESD array achieves an engineering balance between protection and performance through high response speed and extremely low parasitic effects.

   It has been widely used in high-speed interface designs such as USB Type-C, HDMI, Ethernet, and DisplayPort, becoming a standard protection solution for next-generation communication devices.