Custom Drone Flight Controller PCB
System implementation
Overview
A flight controller for an FPV quad, built around an STM32F405 and running Betaflight on a custom target (ETHANF405). There are two 3.3 V LDOs: an AP2112K for the logic and a TLV733P that feeds only the IMU, so switching noise from the MCU never reaches the gyro. That split paid off when the 426xx IMU I designed around went out of stock. Swapping to a Bosch BMI270 meant a new footprint and new decoupling caps, and nothing in the power tree had to change. The ESC I paired it with (a Flycolor Raptor BLS-04) has no BEC, so the board makes its own 5 V at up to 5 A from the 4S pack with a TPS5450 buck. It also has SPI flash for blackbox logs, an i-BUS input for a FlySky FS-iA6B receiver, and solder jumpers that keep each power stage disconnected until I close them on the bench.