On 4/3/07, Peter P. wrote: > Vasile Surducan gmail.com> writes: > > > On 4/2/07, Peter P. yahoo.com> wrote: > > > I have made a schematic for a susceptance tester that closely approximates > > > what and how I tested so others can do this too. Please see attached. > > > > The 5.1V zenner voltage could have any thresold starting from 4.8V to > > 5.3V or so. The ouside impedance between Vdd and Vss( if you like Vss > > against GND) could be any and it's uncontrolable. The current flow to > > opened ESD diodes has a variable flowing path impedance through less > > or higher opened 5.1V zenner. > > I wrote that the circuit where my problems occurred closely resembles the > susceptance testing circuit I posted. The 10 ohm resistor in the supply line is > also there for a reason (besides measuring current). In the real circuit the > zener is the regulator proper (and also the supply overvoltage clamp). > > > If you really want measurements, than use metrological methodes. > > I don't want measurements, I want a simulator that allows me to find out how to > read the datasheet 'between the lines' before making a board that will not work > without 'help' soldered on the back. Usually I strongly prefer to have all the > parts on the parts side and no 'extras', hot stuff, cut traces and wirewrap > bridges. Those appear anyway during prototyping, but this controls their numbers. I understand exactly what do you want, I've made those measurements one or two years back. The right solution is supplying the PIC with a 5V comming from a power operational amplifier output (sinking and sourcing *simmetrical* currents) and a series resistor for measuring exactly the current sourced in normal operation or sunked during the ESD process. It's not an easy measurement because the process is not entirely reproducible and protective diode UI characteristics have a quite abrupt shape at around 0.5V-0.65V voltage drop. Will be one behaviour for small leackage currents (one IO involved in the experiment) and different behavior for all IO pins involved in the experiment. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist