The BU52055GWZ-E2: The BU52055GWZ-: The ROHM BU52055GWZ- is an omnipolar Hall-effect switch that responds to both north and south magnetic poles with a single push-pull output. The output is push-pull, so no external pull-up resistor is needed. Typical applications include lid/cover closure detection in portable electronics, proximity sensing in IoT nodes, and position sensing in consumer appliances where the ambient temperature stays within -40°C to 85°C.
The sensing range is specified as ±5.5 mT trip (operate point) and ±1.5 mT release (release point), tested at 25°C. That 4.0 mT hysteresis gives clean, chatter-free switching as the magnet moves past the sensor. For a typical NdFeB magnet, a 5.5 mT operate point allows an air gap of several millimetres — enough for plastic enclosure walls or thin bezels. The ± sign means the switch triggers on either pole, so magnet orientation does not matter; just bring a north or south field above the threshold and the output toggles.
Package and board integration: UCSP35L1
The BU52055GWZ- comes in a 4-bump UCSP35L1 wafer-level chip-scale package (4-XFBGA / CSPBGA). It is a surface-mount device with a tiny footprint — roughly 1.1 mm × 1.1 mm — suited for space-constrained PCBs in wearables and compact modules. Cut Tape is also available for prototyping or low-volume builds.
ROHM lists the BU52055GWZ- as Active with ROHS3 compliance. The ROHS3 status covers the full substance restriction, including the four phthalates — no exemption paperwork needed for EU-market builds.