On Tue, 30 Dec 2008 01:05:04 -0800 (PST), geordie
put finger to keyboard and composed:

info. 8 pin soic package. pins1,2,3 are connected together,19V input
pin4 control 3.1V
pins 5,6,7,8 connected together output 19V (should be 12V.

That looks like a MOSFET.

Pins 1,2,3 are the Source, pins 5,6,7,8 are the Drain, and pin 4 is
the Gate.

Here is an example (but not your part):
http://www.irf.com/product-info/data...irf7842pbf.pdf

- Franc Zabkar
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