I'm adapting a breakout board for the LMS9DS1 IMU to suit my own needs. This breakout board has an input range of 3-5V and works on 3.3V. However, the circuit, as shown below, seems to have two ways of dropping the voltage. The MIC5225 (bottom left) is a voltage regulator, but don't MOSFETs (BS138, top left) also serve this purpose? What is the purpose of the extra MOSFETs? And can I drop both the regulator and the MOSFETs if I already have 3.3V?
Sorry if this is a silly question.