Waveform Verification for IEC 61000-4-2 Waveshape

Notice: This information is a brief overview. For daily ESD simulator gun verifications and in-depth test information you will need to attain a copy of EN/IEC 61000-4-2.

Procedure

An oscilloscope must use 0% and Max thresholds in order to perform the EMC-specific measurement.

Capturing the correct waveform with the scope can only be achieved with the proper settings of the DSO. The settings need to be made to measure pulses with +/-2kV, +/-4kV, +/-6kV and +/-8kV. Four parameters need to be measured at each voltage level:
- Initial peak current
- Rise time between 10% and 90% of the initial peak
- Current value at 30ns
- Current value at 60ns

The time domain for the initial peak and rise time measurement is recommended to be set to 1ns/Div. For the current measurement at 30nS and 60ns a setting of 10ns/Div is recommended as being appropriate.

Capture a Single Pulse
Measure one pulse, verify rise time for positive pulses, verify fall time for negative pulses
1 GHz, 2 GHz, or 3GHz+ scope depending on standard specification

ESD Waveshape Requirements

Waveshape in accordance to IEC 61000-4-2

Following parameters to be considered when verifying the pulse shape from the ESD generator with an oscilloscope:

First Peak Current
Rise Time (0.6 to 1.0 ns)
Current at 30 ns
Current at 60 ns

Calculating Ratio

Calculated from the impedance and attenuation values the following equation gives the proper ratio:

Ip = 5 x Vm

where
Vm is the voltage signal measured by the DSO in Volt
V1 is the voltage measured accross the CST2 target
Ip is the discharge current

Therefore
V1 = 20dB x Vm = 2ohm x Ip
Ip = 20dB x Vm/2ohm

For example:
A discharge current of 7.5A will give a voltage reading of 1.5V on an ECO2G.

Setup Diagram

Equipment & Materials Needed

Oscilloscope (at least 2 GHz Analog Bandwidth)
Coaxial Current Target Chain
20 dB attenuator (for 16kV ESD Simulators)
30 dB attenuator (for 30kV ESD Simulators)
4' x 4' Vertical Calibration Plane for ESD Target
Tripod for ESD Simulator Gun
Optional Faraday Cage for discharge isolation

Calibration of Current Target Chain

Using an oscilloscope and attenuators - verify the waveform coming off your ESD gun:

Note: Attenuator A should be 20 dB, Attenuator B (typically 10 dB) may not be required.

Related Information

ESD Simulator Gun Calibration Services
IEC 61000-4-2: Test Standard for Electrostatic Discharge Immunity

New to ESD testing?

Virtualy every EE and OEM does ESD testing at one point or other.

In addition to the electrical event, your product is subject to radiated pulse events as well, passing ESD standards is a great start toward a certification.