Hi 'netters,
We are currently experiencing a high failure of a 6-lead RF amplifier IC
assembled on a FR4 laminate. The device itself dissipates about 3.5W, so the
power density is pretty high. The device has a heat slug on its underbelly
for thermal sinking via solder through to the solder pad (surrounded by
inductive vias) onto the PCB ground plane (mechanically interfaced to the
aluminium metal housing). The component is reflowed and subsequently the
solder seeps thru the vias. However, due to PCB design constraints and
'blind soldering', contact between the slug and the solder is inadequate.
Alternatives proposed are to have a hole in the PCB and somehow hand-apply
solder from the bottom, but the design criteria may be compromised, and as
always a quick remedy is sought without design changes. Thermal pads,
thermal paste, thermal glue, hand solder? The solution must also be
electrically as well as thermally conductive.
Any advice eagerly awaited and valued.
Grant
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