LTC3112 undefined behaviour when power supply reaches current limit
I have a similar experience when it operates in boost mode; it gets really hot and, eventually, pin SW2 gets shorted to GND (possibly by internal transistor C getting shorted).
My load is about 10 \$\Omega\$ and I sweep the voltage from 1...12V out, but this happens if \$V_{OUT}&gt;V_{IN}\$.
My best theory so far is that the \$V_{cc}\$ pin starves. There is a mention in the data sheet that a diode forwarding 5V from another source might improve boost functionality.
If you get \$V_{in}\$ dips it possibly also affect \$V_{cc}\$, so it might be something to try. I realize this question is old but it might help someone to be careful about the \$V_{cc}\$ pin on the LTC3112.