Pasi Tamminen

ESD and disturbance cases in electrostatic protected areas

Electrostatic protected area (EPA) can effectively prevent ESD failures from charged operators, work benches and tools. However, electrical disturbances and ESD events from other sources can still exist in well-built EPAs. In this paper failures found in electronic assembly environments are analyzed to improve coverage of ESD control programs.

Charged device discharge measurement methods in electronics manufacturing

Electrical components with a lower CDM ESD immunity can require additional protection methods in manufacturing. Discharge current measurements and electromagnetic pulse detection gives valuable data for more detailed ESD risk assessments. However, both methods require sophisticated tools and trained personnel to get accurate data for control purposes.

The main parameters affecting charged device discharge waveforms in a CDM qualification and manufacturing

Charged device model (CDM) discharges in a CDM qualification and charged device discharges in electronics manufacturing are compared to evaluate the main discharge parameters. Accurate charged device ESD risk assessments would require to use discharge current waveform information and tailored measurement methods.

Charged cable—system ESD event

A charged electronic system failed while it was connected to a USB port. The resulting discharge current waveform had a sub-nanosecond initial peak that bypassed on-board protection devices. In this study the ESD stress waveform is analyzed with simulation and measurement methods.

Charged device ESD threats with high speed RF interfaces

High speed RF interfaces operating in tens Gbit/s range have limited ESD immunity. These interfaces are accessible when electro-mechanics are assembled on a printed circuit board. Charged device ESD threats due to charged assemblies with less than 1 pF source capacitances are discussed in this paper.

Qualification challenges of footwear and flooring systems

Measurement of body voltage alone can result in erroneous conclusions in qualification of footwear and flooring systems in combination with a person. Measurement uncertainties should be taken into account. We have studied the time dependency and charge generation of some footwear and flooring systems. The most significant inconsistencies of the voltage measurement are discussed in this technical paper.

Electrostatic discharge characteristics of conductive polymers

ESD control items are generally characterized by direct current measurements at certain voltage levels. Discharge resistance may, however, have a remarkable voltage and frequency dependency. We have assessed conductive polymers by comparing the resistivities of the solid planar objects with the resistances of electrostatic discharges. Conductive polymers may have applicable characteristics of current attenuation for ESD control items.

Charge relaxation of slowly dissipative polymers

Charge relaxation times of solid planar polymers were assessed with different charging methods in a controlled environment. Electrically isolated samples had relatively long relaxation periods. The longest measurement sequence was 62 hours. An electrostatic behavior of the samples under test was then characterized in a changing electrostatic field.

The effect of USB ground cable and product dynamic capacitance on IEC61000-4-2 qualification

IEC61000-4-2 discharge stress levels are studied with varying product capacitance and ground connections. Stress levels are evaluated based on the measured and simulated peak current, peak power, pulse rise time, and energy transfer along to the USB cable. These stress parameters can be significantly affected by adjusting the test setup.