How hot can CPU module safely run?

When my BeagleBoard B4 is sitting at the boot monitor the CPU module
is hardly warm at all, but when I run the Ångström demo it gets hot.
I don't have a good way to measure its actual temperature, but it's
uncomfortable to leave my finger there more than 4 seconds or so. Now
I'm actually feeling the back of the Micron DDR/NAND module, so maybe
it's what's getting hot refreshing all those pretty graphics.
However, since they're stacked so tightly I figure if one is getting
hot, so are the others.

The DVI driver chip gets quite warm as well, even slightly hotter than
the CPU module. The S-video connector gets warm too, so it must be
conducting heat from the ground plane. BGA packages conduct a lot of
heat through those tiny solder balls.

I do run with the board open to the air. I don't think an enclosed
box is a good idea.

Would it be advisable to add a small stick-on heat sink? As a
hardware engineer, I always like things to run cool so they don't fail
in the field like the XBox a couple of years ago and more recently
nVidia chips.

There has been no indication that a heat sink is needed on these devices. If it makes you feel better, you are free to do so.

They can get a little warm when running full out, but we have seen no issues related to this. If too much power is consumed, then the TWL4030 will shutdown. Most of the heat does come from the Micron device on top. The ground plane does indeed work as a heat sink to pull the heat away from the OMAP device as well as the DVI-D Framer…

How much current is being consumed by the board in this mode?



Thank you for the quick reply. Unfortunately I don't have a decent
multimeter at the moment to measure the current.


OK. When you get a chance let me know. You can measuree the current across the current sense resistor by measuring the voltage drop across J2.