LM1875, Heatsink calculator

[alcuemar]

Dear friends,

I am reading the datasheet the chapter, power dissipation and heat sinking, and I have not clear how to choose the ideal heatsink for each application?

I have a 8 ohm load, power supply +-12V, where i can find the PQ quiescent power dissipation of the amplifier.

Thanks in advance.

[elementx]

any heatsink that does not get hot enough to burn you, that is, if you can remain in contact with it and not scream... it is effective at disipating the heat. any conductive metal with a lot of surface area and some thermal grease is all you need...

I've used little northbridge heatsinks pulled off of old motherboards for smaller 3886 amps that aren't bein cranked on,

[joensd]

National semiconductor has got a calculator for their chips.
Calculates power output, dissipation, etcpp.
It does not support the 1875 directly but for the 1876 it states about 6W maximum output at 1%THD and ~7W max. dissipation/IC.

That´s worst case.
When playing music it shouldn´t get anywhere near hot
with just a piece of aluminium or so.

For maximum output power you´d have to increase voltage rails.
(that´d be ~25V for an 8ohm load)

greets
Jens

[cpemma]

Originally posted by joensd
National semiconductor has got a calculator for their chips.
Calculates power output, dissipation, etc.

Overture Design Guide, Excel spreadsheet.