44E A3144E Hall Element Unipolar Sensor Switch SOT-23

44E A3144E Hall Element Unipolar Sensor Switch SOT-23 is a high-sensitivity magnetic sensing device designed for high-temperature operation and reliable switching in demanding environments. This unipolar Hall-effect integrated circuit senses the presence of a South magnetic pole and provides a digital output signal suitable for direct interface with microcontrollers. Consequently, the sensor eliminates the need for mechanical contact, which significantly extends the operational lifespan of the system. The SOT-23 surface-mount package allows for seamless integration into compact electronic assemblies where PCB space is a premium. Furthermore, its internal voltage regulator and temperature compensation circuitry ensure stable performance across a wide range of supply voltages and thermal conditions. Therefore, you can achieve precise non-contact sensing for speed detection, position monitoring, and proximity applications with this robust component.

Key Features:

• Unipolar Switching: The device responds specifically to a single magnetic pole (South), ensuring predictable and repeatable switching behavior.
• Wide Supply Range: It operates effectively from 4.5 V to 24 V, making it compatible with both low-voltage logic and industrial power rails.
• Open-Collector Output: The output stage utilizes an NPN transistor, allowing users to interface with various logic levels through a simple pull-up resistor.
• Reverse Battery Protection: Built-in protection circuitry prevents damage if the power supply leads are inadvertently reversed.
• Solid-State Reliability: However, unlike mechanical reed switches, this Hall element contains no moving parts and resists physical wear and vibration.

Technical Specifications:

• Supply Voltage (V_CC): 4.5 V to 24 V_DC
• Output Current (I_OUT): 25 mA (Maximum)
• Operating Point (B_OP): ≈ 350 Gauss (Maximum)
• Release Point (B_RP): ≈ 70 Gauss (Minimum)
• Output Saturation Voltage: ≤ 400 mV at 20 mA
• Operating Temperature: −40°C to +150°C
• Switching Speed: ≈ 2 μs Rise/Fall time

Mechanical Specifications:

• Package Type: SOT-23 (Surface Mount Device)
• Number of Pins: 3 Pins
• Encapsulation: Molded Plastic Case
• Lead Material: Solder-plated copper alloy

Dimensions:

• Package Length: ≈ 2.9 mm
• Package Width: ≈ 1.3 mm (Excluding leads)
• Total Height: ≈ 1.0 mm
• Lead Pitch: 1.9 mm (Between outer pins)

Pinout and Wiring:

• Pin 1 (VCC): Connect to the positive power supply (4.5 V to 24 V).
• Pin 2 (Output): Connect to the microcontroller input pin. Additionally, connect a 10 kΩ pull-up resistor between this pin and VCC.
• Pin 3 (GND): Connect to the common system ground.
• Wiring Note: Ensure the magnetic field is perpendicular to the sensor face for maximum sensitivity.

Datasheet Reference:

• Download A3144 Hall-Effect Switch Datasheet

Commonly Used in:

• BLDC Motors: Providing rotor position feedback for commutation in brushless DC motor controllers.
• Automotive Systems: Sensing pedal position, seatbelt latching, and gear selection.
• Consumer Electronics: Detecting the “lid closed” state in laptops and smart mobile device covers.

Applications:

• Tachometers: Counting magnet passes on a rotating shaft to measure RPM.
• Proximity Switching: Replacing mechanical limit switches in CNC machines and 3D printers.
• Flow Meters: Sensing the rotation of internal impellers to calculate liquid or gas flow rates.

Equivalent Models:

• Honeywell SS441A: A unipolar Hall-effect digital position sensor with similar magnetic characteristics.
• Melexis US1881: However, please note that the US1881 is a latching sensor, whereas the A3144 is a switch.
• OH44E: A common direct cross-reference part used in many consumer-grade sensor modules.

Package Includes:

• 1 x 44E SMD hall effect sensor Bi-polar Hall Effect Sensor Switch Hall Element Magnetic Detector 3 Pins Sensor