Silicon Labs 1 Axis Surface Switch/Latch Hall Effect Magnetic Position Sensor, 1.71 V to 5.5 V, SOT-23, 3-Pin SI7201-B-40-IV

The Silicon Labs SI7201-B-40-IV is a single-axis surface switch/latch Hall effect magnetic position sensor, tailored for high-precision positional detection across varied electronics and embedded applications. Housed in a compact SOT-23 3-pin surface-mount package, this device leverages advanced CMOS technology for low-power consumption and features a latch-type magnetic characteristic, making it well-suited for replacing mechanical reed switches, position monitoring, or direct integration into electronic assemblies.

This sensor is designed to operate reliably from a supply voltage of 1.71 V to 5.5 V, allowing compatibility with a broad spectrum of logic and control voltages found in both consumer and industrial systems. Its wide frequency response - ranging from 5 Hz up to 113 kHz - enables both static and dynamic detection tasks, while its exceptional response time of 8.8 microseconds ensures fast reaction to magnetic field changes. With a sensitivity of 1.1 mT and a robust CMOS latching mechanism, the SI7201-B-40-IV can accurately distinguish between magnetic field orientations and produce repeatable digital signals in automotive, HVAC, or appliance controls.

The SOT-23 packaging facilitates automated surface mount assembly, contributing to production efficiency in high-volume manufacturing environments. Its compact form factor, with dimensions of 2.75 mm (L) x 1.6 mm (W) x 1.15 mm (H), ensures minimal footprint on crowded PCBs. The device’s operational range from -40°C to 125°C makes it suitable for harsh industrial, automotive, and outdoor conditions. Standards compliance includes ISO 7637-2-2-11 and Ford EMC-CS-2009.1, underscoring its resilience in challenging EMC environments.

The SI7201-B-40-IV finds application in a diverse set of end uses: as a direct electronic replacement for reed switches in consumer and security products, position and selector knob detection in HVAC and instrumentation, BLDC motor commutation feedback, camera system stabilization mechanisms, and fluid level or mechanical selector switch monitoring. Its latch behavior ensures output changes state only when a magnetic field crosses a defined polarity and strength, aiding in debounce and false-trigger protection.

Overall, this Hall effect sensor is a proven solution for engineers seeking a cost-effective, reliable magnetic switching element with extensive environmental and electrical performance, supporting the rapid development of innovative electronic designs in industrial, commercial, test, automation, and transport sectors.

Browse more Hall Effect Sensors or position sensing solutions from Silicon Labs for advanced electronic design on EnvMart.