I'll be using a 12V power source, as this is an automotive application.
I have the following components:
- ATmega2560, 1.8V-5.5V, 200mA (actually an Arduino Mega 2560, as I couldn't find a through-hole AVR with four UARTs)
- GPS module, 3.3V-5V with 5V-safe inputs, 20mA
- GSM module, 3.4V-4.5V (4.0V is recommended), 3.3V logic, 2A peak
- MCP2515 CAN controller, 2.7V-5.5V, 5mA
- MCP2551 CAN tranceiver, 4.5V-5.5V, 75mA
Everything would be a nice, easy 5V if it weren't for the GSM module, which wants around 4V. So should I use two regulators (a 5V one and an adjustable one set to 4V)? Or if I already have a 5V regulator, is it possible to just use a voltage divider after that for the 4V?
I plan to use a 4050 for level conversion from the MCU to the GSM module (the MCU at 5V reads 3.3V as high).
Would I also require a heatsink? The Arduino's regulator doesn't have one, but it gets hot given a 12V supply.