Under-hood magnetic sensing in a SOT-23-3 footprint
The DRV5033FAEDBZRQ1 is an automotive-grade (AEC-Q100) omnipolar Hall-effect switch from Texas Instruments, responding to both north and south magnetic poles with a single open-drain output. It operates from a 2.7 V supply rail — low enough to run directly from a battery-backed 3.3 V domain without a separate regulator — and draws 2.7 mA typical, making it viable for always-sensing positions like gear-selector position or seat-belt buckle detection. The ±6 mT magnetic trip point (±0.5 mT release hysteresis) sets the detection window: a magnet passing within that flux range toggles the output.
SOT-23-3 package and board integration
The SOT-23-3 surface-mount package (3 pins) mates with a standard 0.95 mm pitch footprint. The open-drain output requires an external pull-up resistor to the logic supply — the 30 mA absolute maximum output current sets the minimum pull-up value: at 3.3 V, a 110 Ω resistor is the floor; a 1 kΩ to 10 kΩ pull-up is typical for most microcontroller inputs.