Check out the ESD note on page 56 of the May 2004 issue of Conformity magazine. It sounds like a mixture of HBM and Machine Model ESD. That is, it appears that people who were charged, and holding a small handheld computer, zapped their big PCs when plugging the serial ports together. The handheld/cable probably acted as a nice TLP (Transmission Line Pulser) having a source impedance of a few hundred ohms and a pulse duration of 7 ns (for a 1 meter cable). I have also noticed that when I hold a metal object I can generate much higher peak currents than just a skin discharge (things were measured with a Peligrini target and 3 GHz oscilloscope).
I have measured myself charged to over 20 kV and this is sufficient to hit 50 amps with the combination above (ouch). Makes me wonder if it is time for a new HBM model and some new generators. Dave Cuthbert Micron Technology
