maybe in a future Intel will release Pentium 23 or something like that, with reduced power dissipation which will cool itself on the mobo ground plane. I can't wait to throw my cpu cooler out the window. Seriously, even if you had forced air through the pcb, it will get dirty and lose a lot of thermal conductivity. I wouldn't rely on that. people expect circuits, especially PIC based which are supposed to be reliable (like in a control system), to not to need active cooling. So i'd avoid that if it were possible On Tue, 18 Jan 2005 00:21:22 +0000, Mike Harrison wrote: > On Tue, 18 Jan 2005 11:47:20 +1300, you wrote: > > >> Does anyone have a guideline for using double-sided 1 ounce copper > >> PCB as a heatsink?? I am going to be using an IRF3170L MOSFET, > >> which has a TO-262 package (about the same size as a TO-220, bit > >> smaller tab) each dissipating about 5 watts. The transistor has a > >> thermal resistance junction to case of 0.75 degree C per watt. > >> Instinct says that we should be able to dissipate 5 watts through a > >> board, but I need to have numbers to back that up. > > > >Very relevant - albeit not the full story. > >Micrel application hint 17 > >Designing PC board heat sinks > > Unless the PCB is pretty big or you have forced air, I think 5 watts is unrealistic. > I start worrying at anything over a watt. > > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist