Diode case...+,-, or Float ?

[wolfblue]

For years I have always let the diode case float with no connection. I have never had a ESD failure with a finished product. But I always hear of people popping diodes when they touch a pointer or a Lab. I have a six year old green that lives with no trouble, case positive of course. But when I build something, I'm still uncomfortable with the thought of my fingers in electrical contact with the die.

Now I'm building something that is frame negative, I would like the diode on the positive side of the MOSFET like normal. The case of the diode would be at ground, but not connected to the die.

I'm not asking for ESD troubles am I?


--John

[shrad]

you should always, in my opinion, have the ground plane at the same potential as the diode can

if the can is floating, then no problem

if the case is negative ground, then the baseplate should be negative ground also

and if the case is positive, either isolate the diode mounts from the baseplate (usually done with peltier devices and nylon screws) or use a negative power supply

[Things]

LasOrb is designed for just this, ESD! They are cheap too, something like $9/each last time I checked.

[shrad]

ESD, yes, but not faults due to bad groundings... and a sporadic contact from a case to the wrong potential can still kill the diode by overcurrent or overvoltage