I have two problems that I need to solve, both involving high-current
circuits:
First, I'm going to be laying down some FETs in SO-8 packages, and I want
a good solid connection from the four drain pins to a surrounding
polygon, both for current flow and to provide a thermal path for heat
sinking. For the same part I want the same solid connection to the
source pins, although I don't need a polygon. Connections that allow
good wide traces (up to 200 mils would be nice) without stomping on the
gate connection would be nice.
Second, I'll be putting in some current sense resistors. While I'm going
cheap and using 2-terminal resistors, I'd like to make a pseudo 4-
terminal device by laying the part out with four pads, but then
connecting pairs of pads with a polygon or some such so that it looks and
solders like a regular resistor, but so that I can have my nice high-
current connections going to it with honkin' big traces, and still have
some thin traces coming off of the pads -- independent of the big traces
-- in a "pseudo Kelvin" connection.
Has anyone solved this problem before? Got any suggestions on how to
proceed?
--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?
Tim Wescott, Communications, Control, Circuits & Software
