When you say short,: how short is short? Measure the I/V characteristic for both polarities. That might give youa hint whether it is "ohmic" or whether a diode is involves. I still maintain that your mystery vendor is imagining things.( I meant ro write something not fit for this newsgroup...) Peter Alfke
good point. we havent measured the continuity in both directions.
the short is real (at least in one direction - from Vcc to ground, less than an ohm)
the cause is, as yet, TBD.
given a complete lack of eveidence for this "capacity-induced failure", it seems more probable that the failures were due to ESD, contamination, miswiring, etc.
How much fault current is the supply capable of?
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
the supply is capable of approx 3A fault current. however, the limit was set to a little over 1A when the fault was first detected.
Was the chip hot after the failure? If not, latchup can be ruled out. The 1 A it may have had may or may not suffice to fry it if latchup has occured (for whatever reason). Some large peak current discharging the power filtering capacitors can have helped, do you have an idea about that (how much capacitance there, that is)?
Dimiter
------------------------------------------------------ Dimiter Popoff Transgalactic Instruments
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