# Heatsink for the TDA2050

#### Booocubs

Joined Dec 11, 2011
14
What heatsink do I need for the TDA2050? I've asked around but people just told me to look in the datasheet and There's a graph showing different ones.

http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXyuqt.pdf (Page 10 is the graph)

That's the link to the datasheet. I'm not sure what heatsink to get; I've never used heatsink's before and I'm really confused.
I will be using this circuit, shown to me by AudioGuru;

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Except I will be powering 36 Bright Blue LED's, in group's of three, with a 100ohm resistor in front of each group.

#### bountyhunter

Joined Sep 7, 2009
2,512
You have to know your max power dissipation and then go shopping for a heatsink (AAVID, thermalloy, wakefield, etc).

Example: suppose max power dissipation is 10W. Thermal resistance junction-case for the TO-220 device is 3C/W. Add 1C/W for the insulator mounting it to the haetsink. That uses up 4C/W. Assume maximum allowable junction temp is 125 and ambient is 25C, you can tolerate 100C rise above ambient from 10W power. This means the TOTAL thermal resistance is 10C/W allowed. Since 4C/W is already used up, your heatsink must be 6C/W OR LESS thermal resistance. The data sheets on heatsinks give the data to calculate this value.

#### Audioguru

Joined Dec 20, 2007
11,248

I assume you are using a 12.0V supply and I assume that your blue LEDs have a forward voltage of 3.3V each. Then their current is (12V - 9.9V)/100 ohms = 21mA.

36 LEDs are in 12 strings and their total current is 252mA which is not much.

If you don't play acid rock at full blast all the time then the average output current from the IC will be only 84mA because the circuit is a rectifier and the average current will be about 1/3rd the peak current because only the peaks of the music lights the LEDs for only a moment. Then the heating is very low and a heatsink is not needed.