MOSFET Selection Guide for Power Tools and BLDC Motor Drives

How to Protect Electronics from ESD

Electrostatic discharge (ESD) is one of the leading causes of electronic system failure. As devices integrate USB PD up to 48 V, USB4 high-speed differential pairs, Automotive Ethernet, and increasingly compact connectors, designing ESD protection early is essential to meeting reliability and compliance requirements.

This page explains what ESD protection is, how to design ESD protection, what kind of diode is used for ESD protection, and how to protect circuits and electronics from ESD across USB-C, Ethernet, video, and other high-speed interfaces.

It also provides guidance for selecting MCC ESD protection diodes, TVS diodes, and overvoltage protection (OVP) devices.

What Is ESD Protection and Why It Matters

ESD protection refers to the design practices and components, primarily ESD protection diodes, TVS diodes, and OVP devices that prevent electrostatic discharge from damaging sensitive electronics.

Real-world ESD events can exceed tens of thousands of volts with sub-nanosecond rise times. Without proper protection, ESD and electrical overstress (EOS) can cause:

IC and transceiver damage
USB port failures
Ethernet PHY failures
Latch-up events
Long-term reliability problems

There are several models developed to simulate an ESD event. Below table shows the industrial standards:

ESD model	Application level	Simulated event	Test conditions	Peak voltage	Peak current	Stored energy
HBM (JS-001)	Component level	A person who has built up static charge (e.g., by walking on a carpet) and then discharges that energy directly through their finger when touching an electronic device	100 pF / 1.5 kΩ Tr = 2–10 ns Td = ~150–200 ns	Up to 8 kV	~5.3 A (at 8 kV)	3.2 mJ
CDM (JS-002)	Component level	A scenario where the device itself becomes charged (e.g., sliding down a production line) and then discharges all its stored energy instantly when one of its pins touches a grounded surface	Device‑dependent* / < 1 Ω Tr = 0.1–0.5 ns Td = ~1–8 ns	Up to 1 kV (or higher)	5–20 A (at 500 V)	~2 µJ (for 4 pF at 1 kV)
IEC 61000-4-2	System level	A more energetic event where a charged person, often holding a metal tool like a key or screwdriver, discharges directly into a finished, operational electronic product	150 pF / 330 Ω Tr = 0.7–1 ns Td = ~60–100 ns	Up to 30 kV (air)	~30 A (at 30 kV)	67.5 mJ
ISO 10605	Automotive system level	A discharge from a charged metal object (like a repair tool, fuel nozzle, or a car's metal door frame) to an electronic module inside a vehicle	330 pF / 330 Ω Tr = 0.7–1 ns Td = ~50–100 ns	Up to 30 kV	~112.5 A (at 30 kV)**	148.5 mJ (at 30 kV)

ESD Waveform comparison 0-200ns mcc semi-1

Initial ESD Waveform comparison 0-30ns - mcc semi-1

ESD Waveform Comparison (0-200ns) @30kV Max Stress

Initial ESD Waveform Comparison (0-30ns) @30kV

Internal IC protection is designed only for device-level HBM and CDM handling events and cannot withstand IEC 61000-4-2 system-level ESD exposure through external connectors. External ESD and TVS protection devices are required at every exposed interface.

How ESD Damages Electronics

To design ESD protection effectively, engineers must understand the underlying failure mechanisms.

1. Direct Overvoltage Stress

Voltage spikes exceed breakdown limits of semiconductor structures.

2. High Transient Current

Fast current pulses damage internal metal layers and I/O protection cells.

3. Capacitive and Inductive Coupling

ESD energy can couple into high-speed lines without direct contact.

4. Connector Injection Points

USB-C, RJ45, HDMI, and DisplayPort connectors are common paths for ESD energy to enter a system.

5. Real-World Failures

Damaged ports
PHY failures
Signal degradation
Intermittent or latent failures that may pass production testing but fail later in the field

How to Design ESD Protection

1. Identify All ESD Entry Points

Common exposure points include:

USB-C ports
Ethernet jacks
HDMI, DisplayPort, and LVDS connectors
LEDs, buttons, and open-drain outputs
Sensor interfaces
Test pads and housings

2. Choose the Correct Protection Devices (ESD Diodes and TVS Diodes)

Both ESD protection diodes and TVS diodes are commonly used to address different transient threats within the same system.

ESD Protection Diodes

Ultra-low capacitance
Ultra-fast response
Optimized for high-speed interfaces such as USB4, HDMI, DP, DisplayPort, and Ethernet

TVS Diodes

Handle larger surge energy
Protect power rails such as VBUS and automotive supply lines
Complement ESD diodes in mixed-transient environments

In practice, ESD diodes are selected primarily for speed and capacitance, while TVS diodes are selected for energy handling and voltage rating.

Learn more about selecting between TVS and ESD devices here: Understanding TVS Diodes – A Comprehensive Guide

3. Match the Device to the Interface

High-Speed data lines, control signals, and power rails require different protection strategies. The table below outlines which protection devices are best suited for each common interface.

Interface	Recommended Device
USB4 and USB3.x	Ultra-low capacitance ESD diodes below 0.3 pF
USB-C CC and SBU	Overvoltage protection devices
USB PD VBUS 5 to 48 V	High-Ipp TVS diodes
Automotive Ethernet	Low-capacitance ESD diodes meeting OPEN Alliance requirements
1 to 10 GbE	Ultra-low capacitance ESD diodes between 0.15 and 0.25 pF
HDMI, DP, LVDS	Ultra-low capacitance ESD diodes below 0.20 pF
Open-drain outputs	Unidirectional ESD diodes
LEDs	Small-signal ESD diodes

4. Follow ESD PCB Layout Best Practices

Correct PCB layout ensures ESD energy is safely diverted away from sensitive components. Without proper placement and routing, ESD protection devices cannot function effectively.

Place ESD devices as close as possible to the connector
Minimize inductance by keeping traces short
Maintain symmetry on differential pairs
Provide a low-impedance ground path
Avoid routing ESD discharge currents near sensitive circuitry

5. Validate Using System-Level Tests

System-level validation ensures that ESD and surge protection strategies remain effective beyond the schematic. Testing verifies immunity, compliance, and long-term reliability.

IEC 61000-4-2 ESD
IEC 61000-4-4 EFT
IEC 61000-4-5 surge
USB and Ethernet compliance
Automotive EMC tests

USB ESD Protection for USB-C, USB 3.x, and USB4

USB-C combines high-voltage power delivery, sensitive control signals, and multi-gigabit data channels within a compact connector. This combination makes USB interfaces especially vulnerable to ESD, electrical overstress, and hot-plug events, particularly when CC and SBU pins are exposed to transient shorts with VBUS during insertion or removal.

Effective USB ESD protection requires a coordinated approach that includes overvoltage protection for CC and SBU pins, high-current TVS diodes for VBUS rails up to 48 V, and ultra-low-capacitance ESD diodes for USB 3.x and USB4 differential pairs to preserve signal integrity.

A detailed design guide with device recommendations, placement strategies, and automotive considerations is available here:

Next-Gen USB ESD Protection: Tailored Solutions from MCC

Ethernet ESD Protection from 100BASE-T1 to 10GbE

Ethernet interfaces are highly sensitive to ESD because even small parasitic capacitances can degrade differential signaling, especially at gigabit and multi-gigabit speeds. ESD can enter through RJ45 connectors, cable shields, or LED control pins and propagate toward the PHY if not properly suppressed.

Robust Ethernet ESD protection focuses on ultra-low-capacitance ESD diodes placed on the secondary side near the PHY, with strategies that balance immunity against IEC 61000-4-2 requirements while maintaining return loss and insertion loss performance. Automotive Ethernet adds further challenges, requiring compliance with OPEN Alliance EMC guidelines and resilience to higher discharge levels.

Recommended protection approaches and device examples are covered in detail here:

Ultimate Ethernet ESD Protection: High-Performance Devices from MCC

Video and Display ESD Protection for HDMI, DisplayPort, and LVDS

High-speed video and display interfaces operate with extremely tight signal integrity margins, making them some of the most ESD-sensitive connections in modern electronics. Even minimal capacitance or asymmetry introduced by protection components can distort eye diagrams and reduce link reliability.

ESD protection for video interfaces requires ultra-low-capacitance ESD diodes placed directly at the connector, with careful attention to symmetrical loading across differential pairs. These devices must provide fast clamping for connector discharge events while remaining electrically transparent at high data rates.

Design considerations and optimized solutions for video and display interfaces are explored here:

Next-Gen Video ESD Protection: High-Performance Solutions from MCC

Explore MCC ESD and TVS protection devices for high-speed, power, and automotive applications.

ESD Protection: How to Design Robust ESD, Surge, and Overvoltage Protection for Modern Electronics

Practical guidance for engineers designing USB-C, Ethernet, automotive, industrial, and high-speed interfaces