@sterretje Thanks for moving the topic properly. I've already tried both voltages. However it should not make any difference cause there should be a regulator on the breakout board which reduces the voltage properly.
A voltage regulator and 5V tolerant pins allow you to use it with 3.3V or 5V microcontrollers or single board computers. Overview | EMC2101 Fan Controller and Temperature sensor | Adafruit Learning System
The schematic looks ok. AP2112K-2.3 should simply "pass-through" the 3V3 in case VCC is powered with 3V3.
