The MRMS501A‑001 is an AMR anisotropic magnetoresistance digital magnetic switch sensor from Murata.

 Core Functions

Magnetic‑field Detection with Digital‑switch OutputIt detects external magnetic fields based on the AMR magnetoresistive effect. When the magnetic‑field strength reaches the threshold, the output level toggles. It outputs high/low digital levels directly to MCU I/O ports without external op‑amps or peripheral signal‑conditioning circuits, simplifying the BOM.

Logic: Inverting‑logic output. The output goes low when the magnetic field reaches the trigger threshold; the output returns high when the magnetic field is removed. Logic handling shall be considered in software development.

Non‑polarized Magnetic‑pole Detection (Key Advantage)Triggering occurs with either the N‑pole or S‑pole approaching, so strict magnet‑orientation alignment is not required. Compared with Hall‑effect switches, it offers greater flexibility for magnet placement, higher assembly tolerance in production and fewer mechanical‑structure‑related issues.

Ultra‑low Power Consumption for Battery‑powered DevicesTypical average operating current is 3 μA @1.8 V. Its micro‑ampere‑level power consumption avoids excessive power drain for long‑term operation of battery‑powered equipment.

On‑chip IC for Automatic Sampling and JudgmentThe IC integrates AMR magnetoresistive elements and processing circuitry to sample magnetic fields periodically. The minimum response frequency is 8 Hz. It is suitable for low‑speed position and open‑close detection, but not for high‑speed rotation or high‑frequency applications.

Wide‑voltage CompatibilitySupply voltage ranges from 1.6 V to 3.5 V. It can interface directly with 1.8 V and 3.3 V systems and supports lithium‑battery‑powered devices.

2. Key Specifications

Package: Mini‑FLP‑3, dimension 1.45 × 1.20 × 0.55 mm, 3‑pin SMT surface‑mount device; 3000 pcs per Tape&Reel reel.Supply voltage (VCC): 1.6 V ~ 3.5 V, typical 1.8 V.Average operating current: 3 μA (typical), maximum 8 μA.Operate magnetic field (Hon): max. 2.5 mT; Release magnetic field (Hoff): min. 0.5 mT.Output: Push‑pull digital output, inverting logic.Response frequency: minimum 8 Hz.Operating temperature: ‑40 ℃ ~ +85 ℃, industrial temperature range; non‑automotive‑grade, no AEC‑Q100 qualification.Storage temperature: ‑40 ℃ ~ +125 ℃.RoHS compliant.

3. Application Scope

✅ Preferred Application ScenariosOpen‑close Detection (Most Common Use‑case)Lid‑open/closed detection for notebook PC screens, tablets and game consoles. When the lid closes, the approaching magnet triggers the sensor for system screen‑off and power saving; when the lid opens, the magnet moves away to wake‑up the screen.

Home‑appliance Door / Cover DetectionDoor‑status detection for refrigerators, dishwashers, rice cookers and water‑heater panels. A trigger signal is generated when the door is closed. The MCU recognizes door status for safety interlock alerts.

Position Detection for Portable Battery‑powered DevicesCover detection for smart door locks, portable instruments and charging cases. Ultra‑low power consumption makes it ideal for battery‑operated products.

Position Sensing for Small‑sized Industrial EquipmentCover‑open detection and tamper‑proof detection for industrial equipment. A signal is output upon magnet approach to identify whether the enclosure has been opened.

Consumer Small Home AppliancesLid‑in‑place detection for coffee machines and food processors. Equipment startup is permitted only after correct accessory installation is confirmed.