An experimental and theoretical consideration of physical design parameters in field-induced charged device model ESD simulators and their impact upon measured withstand voltages

Study of CDM specific effects for a smart power input protection structure

“…However, the comparability of CDM measurements with circuit simulation results is compromised due to the nonlinear and poorly reproducible discharge arc, occurring during the measurements. Carey [9] showed that this results in high variations of the discharge current amplitudes and peak current saturation effects above CDM voltages of approximately 1000-1500 V. Furthermore, the bandwidth of the oscilloscope distorts the recorded transient CDM discharge current signal significantly. For a sufficient agreement of simulation and measurement, the nonlinear arc resistance and the low pass filter formed by the oscilloscope have to be considered for simulation.…”

Issues concerning CDM ESD verification modules-the need to move to alumina

“…Collected data reveals a major change in peak current (Ip) value for a FR-4 dielectric after exposure to moisture for 24 hours. The FR-4 material also has a dielectric constant dependent on frequency (see Table 6), as specified [9] and demonstrated by Carey and DeChiaro [6]. Since the energy and waveform shape of the CDM discharge event is dependent on the dielectric constant of the verification module, a more stable dielectric constant is required.…”

“…Since capacitance, metallic disk flatness, dielectric thickness, and FR-4 dielectric constant values are not given in the JEDEC standard (see Table Al), certain assumptions had to be made. These assumptions include use of dielectric constant values as calculated for the ESDA COM (5.10 and 5.68) and previously published JEDEC dielectric thickness values [6]. Based on this data, it is deduced that the thickness of the 6-in.…”

“…Dielectric thickness values o f t = 0.8 mm, as specified for ESDA (see Table A2), and t = 0.015 in (0.381 mm), from published data on JEDEC testing [6], were selected. It is well established that the dielectric constant of FR-4 material ranges from 3.6 to 5.5 [9].…”

“…To investigate the power-law dependence of peak current [6] on the COM capacitance value, capacitance values were measured for fifteen different COMs from various vendors and lab locations. The capacitance values ranged from 3.31 -4.58 pF for the small COM (4 pF) and from 15.60 -33.20 pF for the large COM (30 pF).…”