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I read through your application note AND8307/D: Characterization of ESD Clamping Performance because we would like to do similar testing on our circuit boards to compare various protection devices and PCB layout techniques. The test procedure describes the use of an attenuator at the oscilloscope to protect the scope's analog input channel. Can you provide a part number of an attenuator that you use for these tests? I have done a little research into these parts and I have been finding that they can only hand tens of volts and not the thousands of volts that would be present in the test setup. Thank you.

An attenuator which we have used is from JFW Industries, model number 50FPE-020 SMA. This is a 5 W, 20 dB attenuator with a 6 GHz maximum frequency. Most 5 W attenuators will work for this application. Depending on the maximum input voltage of the oscilloscope, the clamping performance of the protection device being measured and the maximum ESD gun stress voltage it may be necessary to use two of these attenuators in series to ensure that the measured voltage does not go off scale.

The power ratings of attenuators are often continuous power dissipation values rather than the power delivered in a short pulse such as an ESD event. Since an ESD event is so short, under 100 ns, these attenuators can absorb considerably more power than the rated power. The protection device being studied should also be diverting most of the current away from the attenuator since most protection devices have impedances well below the 50 ohm input impedance of the attenuator. It is always a good idea, however, to start out with low ESD gun stress voltages to check out the test setup and then work up to the desired stress voltage
Answered by:
ON Semiconductor
2014-01-28 12:34:20.944