I've been reading about power supply requirements for RPi and want to learn more about the practical limits in addition to the design limits. What is the power protection circuit (if any) on the micro-USB port, what is the maximum voltage it will tolerate?
I have set up a test power supply (using a bench power supply, 7.5A (18AWG) leads to a micro-USB headshell). So I can see the relatively exact supply details. I've measured the voltage at the RPi micro-USB, and noted a 0.1V cable loss at 5.5V supply, so I believe my test cable can carry sufficient power.
While exploring the under-power situations described in a lot of articles on the web, I've varied the input voltage from 5V to 5.5V (which seems stable), and briefly risked up to 6V without frying the RPi. I am interested to know at what point I can expect smoke.