Which regulator to use from 12v to 4.2/2.5A and to 3.3V
I used diffrent regulators, my input voltage is 9v the regulator that i used to power the MCU is MIC5203-3.3YM5 and the schematic i used is in the datasheet, to power the SIM i used mic29302 this regulator convertts my input of 9v to 4V. In the datasheet you have the schematic for this regulator.