Heatsink requirements for amp7 and amp15

[more10]

How big heat sinks are needed for amp15 and amp7?

[krilli]

Are you interested in an estimate by mr. some uneducated guy? (That would be me.)

If we assume 80% efficiency of MAX_POWER, then ~ 20% of MAX_POWER is heat.

Amp7 is 2x500 = 1000W max, so we could conceivably see 200W of waste heat at full tilt. Then you could conceivably plug in the temperature spec, and find out a ballpark degrees per watt ...

The worst case heatsink for Amp7, assuming that maximum temp is 130 degrees, and 30 deg ambient, would be 0.5 degrees C per watt. When playing full-tilt sinewaves at 1000W into an inefficient load.

For Amp15, 2.5 degrees C per watt.

Hope this helps rather than hurts. I don't know enough to be talking about this really ...

[wadoka]

Want an even less reliable estimate?

Amp7...dont know.

Amp15 I am using a 3mm thick aluminium plate the same size as the amp15's pcb. It doesnt even get warm, so it must be overkill.

[more10]

Thanks guys, krillis maths appears to be solid :-)

[more10]

I intend to mount the apms on a heatsink that is a bit larger than the amp, in order to be able to mount the heatsink without any problems on the front plate of a 3U 19" case.

Aavid heatsinks for amp7: http://www.aavidthermalloy.com/cgi-bin/euro2_exsrch.pl?Pnum=&PgNum=1&NumPerPage=v3&LengthUnits=mm&ExLength=130.00&WidthMin=170.00&HeightMin=0.00&WidthMax=210.00&HeightMax=999.00&ThermalResist=1&CType=Natural&AirFlow=&AirUnits=ms&Shape1=ON&Shape2=&Shape3=&Shape4=&Shape8=&Shape5=&Shape6=&Shape7=&SortBy=V2&PartClass=A&ClassA=0&ClassB=0&ClassC=0

Heatsinks for amp15: http://www.aavidthermalloy.com/cgi-bin/euro2_exsrch.pl?PgNum=1&PartClass=A&ClassA=0&ClassB=0&ClassC=0&LengthUnits=mm&WidthMin=170&WidthMax=210&HeightMin=&HeightMax=20&ThermalResist=2%2C5&ExLength=130&CType=Natural&AirFlow=&AirUnits=ms&Shape1=ON&SearchButton1=Search&SortBy=V2&NumPerPage=v3. I guess this is overkill :-)

[V-bro]

AMP7 is fine with a sheet the size of the PCB in 2 or 3mm aluminium.... It's just always stone cold...

I do normally give it some more to be sure...

------X-max. can be several meters on any driver, too bad it can be done only once...------