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Triboelectric charging occurs when two materials make contact and separate Electrons from one material are transferred to another leaving one positively

charged and the other negatively charged.– The nature of the materials will determine who losses or gains electrons

The build up of static electricity is determined by several factors such as: area of contact, the speed of separation, relative humidity, and chemistry of the materials, surface work function, etc.

*Table from ESDA

What is ESD and where does it come from? – Triboelectric Charging

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ESD Standards – Human Body Model, MIL-STD

Based on Skin-to-Metal Contact– e.g. Person touches pin of IC, discharging directly to pins

Used in Military Standard (883E) test specification Addresses the Manufacturing/Production environment;

testing is done directly on the IC Circuit Model:

Discharge Voltage Peak Current 500V 0.33A 1,000V 0.67A 2,000V 1.33A 4,000V 2.67A 8,000V 5.33A

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Based on Metal-to-Metal Contact– e.g. Person with tool/key in hand discharges to I/O port

Used in IEC 61000-4-2 test specification Addresses the user-environment; testing is done at the

application or system level Circuit Model:

Discharge Voltage Peak Current 2,000V 7.5A 4,000V 15.0A 6,000V 22.5A 8,000V 30.0A

ESD Standards – IEC 61000-4-2

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IEC 61000-4-2, continued

Discharge Voltage First Peak Current, 30ns Current, 60ns 2,000 V 7.5 A 4 A 2 A 4,000 V 15.0 A 8 A 4 A 6,000 V 22.5 A 12 A 6 A 8,000 V 30.0 A 16 A 8 A

Specified current values, per discharge voltage

Most all manufacturers test to 8kV or higher!

ESD Standards – IEC 61000-4-2 Waveform

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Peak current Peak currentDischarge Voltage Human Body Model IEC 61000-4-2 500 V 0.33 A 1,000 V 0.67 A 2,000 V 1.33 A 7.5 A 4,000 V 2.67 A 15.0 A 8,000 V 5.33 A 30.0 A

The key here is that a chipset that survives Human Body Model testing (in the manufacturing environment) is not guaranteed to survive in the field, where the exposure to ESD will be much more severe.

Different models yield much different peak current values; ultimately electrical stresses on the chipset are very different.

ESD levels in the field far exceed the values that can be generated in the manufacturing environment.

Comparing the Two Specifications – IEC 61000-4-2 vs. Human Body Model