Re: Ethermega fried the 5v regulator
Posted: Fri Mar 29, 2013 10:50 am
No voltage on those pins.cef wrote: If anyone gets this issue and wants to confirm if the regulator is working, you can put a multimeter between the DC IN pin (on the jumper header that selects between USB / DC IN power) and Ground to see if there is any voltage coming out of the regulator.
So 8 Volts should be more than enough head room. I'm 2Amp power supply which drops the voltage from 12 volts. The 240V AC to 12V DC is a switch mode device.cef wrote: The DC jack on the board is protected from reverse polarity by a 1N4004 diode, but the VIN pin is NOT. If you put a negative voltage on the VIN pin (between Ground and Analog 0 on the shield header), you may fry the regulator.
Mikecef wrote: The 1N4004 diode will drop somewhere between 0.8 and 1.1 Volts. The regulator (EUP3476) seems to need at least a 0.8 Volt difference between input and output (at least, the way I'm reading the spec sheet) so you probably need a supply a minimum of 1.9 Volts higher than what is needed out (5 Volts in this case, so 6.9 Volts in) if you use the DC Jack. Note that while a DC plugpack may say it supplies a specific voltage, that may be only under ideal conditions (eg: exactly 240V supply, no load, etc), so you may want to check your actual input voltage under load (eg: across the DC Jack pins while plugged into the EtherMega) if you have issues.