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Registered Member #191
Joined: Fri Feb 17 2006, 02:01AM
Location: Esbjerg Denmark
Posts: 720
Just got a 25W half brick and a 50W full brick, and I have never worked with these things before. I hear they are a b*tch to mount. but worse case dissipation is only 5W and 10W respectively. 10W from an 8sq in surface doesn't sound much? do I really need a heatsink for them?
We used them all the time. Two serious warnings. Do not bend them! The mounting surface must be flat so they do not warp the base plates. The other side is a ceramic plate so it cracks... A big blob of heat sink grease in the center can cause enough hydraulic pressure to bend up the center, so go super light on the grease and torque them down over hours so the extra grease can squeeze out gracefully . Mounting holes should have counter sunk ridges so there are not shoulders that hold them up. The base of the bricks is probably warped inward do the the ceramic attach and soldering temperature and the thermal contraction as it cooled. That is normal and it does no harm.
Of course, at 5 or 10 watts such things are easy... Just use a super light coating of grease and very low screw torque. The probably do need some heat sinking since their free air thermal dissipation is very poor.
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