thanks for the reply
Yes it can sink up to 120mA but it seems it can do this only if not all channels are on at the same time.
After playing a little bit more with the heat equation, i realized that output voltage matters alot with this chip. But since i dont know the output voltage (since its njot in the datasheets) i just played around.
And figured if i only have 15 channels on an use 20mA per channel (which is for 10 cm strips) and assume of the 12 volts only 6 remain, it would work.
Or the heatsink approach.
but i dont know about heatsinks, are there special heatsinks for ics ? like there are for normal cpus ? or is there more like one heatsink matching one ic ?
if all fails, would the transistor approach work ?