Interpretation|The new version of the IEC standard for electrostatic testing has stricter requirements for electrostatic gun calibration

The IEC electrostatic standard has not been updated for more than ten years, and there are still some changes in the overall layout compared to the previous version. Follow me to learn about the changes that need to be focused on:

Table 2 - General ESD generator parameters

Table 3 Discharge current waveform parameters

Observant you should have already noticed:

• The contact discharge in Table 2 has been updated from 1 kV to 2 KV at least initially;

• The yellow section in Table 3 has added calibration requirements for ESD generators with air discharge tips;

• It can also be seen from Table 3 that for electrostatic guns supporting up to 15 kV, 15 kV waveform calibration is required.

Take a look at the waveform diagram of the 4 kV calibration current for electrostatic contact discharge in the new standard:

At the same time, some updates have been made to the current calibration program;

Of course, for the open circuit output voltage, it is necessary to measure the open circuit output voltage of the ESD generator when the discharge switch is closed and meet the requirements of Table 2.

Measurement steps for current waveform parameters of ESD generator:

1. Record the waveform of five discharges (five positive and five negative polarity).

2. Measure the following parameters (see Figure 2 and Table 3) and ensure that each value is within the allowable range:

• Ip1: First peak current (A)

• Ip2: Second peak current (A)

• I30: Current at 30 ns after discharge (A)

• I60: Current at 60 ns after discharge (A)

• TR: Current rise time (ns)

3. At least one waveform of 8 kV positive polarity contact discharge should be included in the calibration report.

The measurement of Ip2 points has been added to the calibration program, and the 2025 standard emphasizes that at least one waveform of 8 kV positive polarity contact discharge should be included in the report.

Let's compare some changes in the calibration target board configuration between the 2025 and 2008 versions:

IEC 61000-4-2:2025

IEC 61000-4-2:2008

The new version has added normative attachments for specific equipment testing devices

Small wall mounted EUTs; When EUT<(0.5*0.5) m, the center of VCP should be located at the center of both sides of EUT.

Wall mounted equipment should be installed on walls without conductive structures or embedded in walls, and should be set up according to the example shown in Figure I.1;

NOTE A  Similar insulation brackets can be used, but without metal plates, as shown in Figure I.2.

If the EUT is intended to be installed on a conductive surface, the test setup is shown in Figure I.2,the size of the metal in Figure I.2 should exceed the EUT by at least 0.5 m in all directions.

Other differences between IEC 61000-4-2 2025 and the previous version:

• Added an informative annex on how to select test points and give guidance on how to specify the number of pulses for direct contact discharges (see Annex E);

• Moved Clause 9 into a new informative annex (see Annex K);

• Improved measurement uncertainty considerations with examples of uncertainty budgets;

• Moved post-installation tests into a new informative Annex G since they cannot be performed in a controlled environment.

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