Hi,
An audio circuit I'm designing is pulling around 100mA at 5v and, for various reasons my only power source is 12v.
In my prototype I used an AMS1117-5.0 which is a SOT-223. It is therefore dissipating around 0.7W. It gets pretty hot, though you can still touch it and I've not seen it go into thermal shutdown.
I don't really want to use a buck converter, as I'm concerned about electrical noise.
I wasn't terribly careful about the prototype PCB design, so I could doubtless improve the thermal layout of the SOT-223 footprint (larger 5v Pad, vias through to matching underside area etc).
My question is: Is it better to go for a better thermal design, or should I look at, say, dropping the 12v to 8v or 10v via an LM2937 before hitting the AMS1117-5.0 that way I have two SOT-223 packages, the LM2937 dissipating 0.4W and the AMS1117 dissipating 0.3W (or thereabouts)?