LF: FETs failing

["Alan Melia" <Alan.Melia@btinternet.com>]

Hi All, Jim has raised an interesting point about low current testing which
probably applies to BJT RF devices as well in some cases. A lot of these
devices consist of several small fets (or smaller BJTs) in parallel on the
chip. It is possible to have some of these go open (BJTs suffer breaks in
their emitter metallisation due to electro-migration of the contact metal)
Breaks in source, or emitter, paralleling track on the chip could mean that
the unit could look ok at low currents, but be overloaded when run at full
blast.

Cheers de Alan G3NYK
alan.melia@btinternet.com