Voltage Levels on NEO m8N with HMC5983 Compass

I recently bought a NEO M8N with HMC5983 Compass. On a picture in the Internet i saw a solder pad, to choose between 3.3V and 5V Input. Mine dows not have such a pad. I’m using a Teensy 3.5 with 3.3V Logic Level. Is the logic Level of I2C and the RX/TX always 5V or can I change the logic level? Is the Input supply voltage 5V or can it be 3.3V as stated in the guide pdf? Or is the logic level always the supply voltage?


The version with a solder pad is an old version that is no longer sold. On your board there is a voltage regulator turning 5V into 3.3V in order to supply power to GPS chip + compass. Logic levels are 3.3V.

Can I operate the module directly with 3.3V?

It is not recommended because there is a 3.3V LDO regulator behind the power supply pin.