S41 Bipolar Hall Effect Position Sensors TO-92S

S41 Bipolar Hall Effect Position Sensor, housed in the compact TO-92S package, offers a reliable and precise solution for magnetic switching and sensing applications. Unlike unipolar sensors, this device operates using a bipolar magnetic field, requiring both a North and South pole field to cycle the output between ON and OFF states. This feature provides superior noise immunity and precise position sensing, making it an excellent component for detecting rotor rotation, speed, and positioning in various electromechanical systems. You can easily integrate this low-power sensor into battery-operated systems and demanding industrial controls where accurate, contactless switching is essential for long-term reliability.

Key Features:

• Bipolar Latching: The sensor requires an alternating North ($B_{\text{RP}}$) and South ($B_{\text{OP}}$) magnetic field to toggle its output state, significantly enhancing switching precision and stability in rotational or reciprocating motion systems.
• Solid-State Reliability: As a contactless device, it eliminates mechanical wear, offering virtually unlimited operating life and high immunity to dust, moisture, and vibration.
• High Sensitivity: It detects small changes in magnetic flux density, a crucial factor allowing you to utilize smaller, less costly magnets or achieve greater air gaps between the sensor and the magnet.
• Wide Operating Voltage Range: Functions efficiently across a broad power supply range, typically 4.5 V to 24 V DC, readily accommodating various microcontrollers and industrial logic voltages.
• Miniaturized Package (TO-92S): The small footprint and slim profile make this a superior component for space-constrained product designs where a traditional TO-92 would be too large.

Technical Specifications:

• Output Type: Open-Collector (NPN), which requires a pull-up resistor. This design allows the output to interface with various logic levels.
• Operating Voltage (V_CC): 4.5 V to 24 V DC (Typical range).
• Output Sink Current (I_OUT): 20 mA maximum (Can directly drive LEDs or small loads).
• Magnetic Flux Density (Operating Point B_OP): Typically +5 mT (South pole).
• Magnetic Flux Density (Release Point B_RP): Typically −5 mT (North pole).
• Switching Hysteresis (B_HYS): An integrated hysteresis loop ensures clean, bounce-free switching.

Mechanical Specifications:

• Package Style: TO-92S (Flat transistor package).
• Pin Pitch: ≈ 1.27 mm (Standard for S-package).
• Mounting: Through-hole device, designed for mounting on PCBs.
• Operating Temperature Range: −40°C to +85°C (Industrial grade).

Dimensions:

• Body Height: ≈ 3.0 mm.
• Body Width: ≈ 4.0 mm.
• Body Thickness: ≈ 1.5 mm.
• Lead Length: ≈ 15 mm (Typical).
• Weight: ≈ 0.2 g.

Pinout and Wiring:

• Pin 1 (V_CC): Connect this pin to the positive power supply (4.5 V to 24 V).
• Pin 2 (GND): Connect this pin to ground (0 V).
• Pin 3 (Output): Connect this pin to your load (e.g., microcontroller input or LED) using a pull-up resistor to V_CC. The output switches LOW (to ground) when activated by a magnetic field.
• Wiring Note: Always utilize a small pull-up resistor (e.g., 10 kΩ to 1 kΩ) between the Output pin and V_CC for the open-collector output to function correctly.

Datasheet Reference:

• Download S41 Bipolar Hall Effect Sensor Datasheet

Commonly Used in:

• BLDC Motor Control: Detecting rotor position for commutation in brushless DC motors.
• Automotive Systems: Sensing speed for anti-lock braking systems (ABS) and transmission.
• Metering Devices: Used in utility meters (water, gas, electricity) to count rotations.

Applications:

• Speed and RPM Sensing: Accurately measuring the rotational speed of shafts and gear trains.
• Position Detection: Determining the presence or absence of a magnetic object in machinery.
• Flow Sensing: Counting pulses from a flow meter turbine that contains a magnet.

Equivalent Models:

• SS41F: A very common and comparable bipolar latching sensor often used in magnetic field sensing applications.
• A1203/A1204: Bipolar latching Hall-effect switches known for their stable performance and wide temperature range.
• US5881: Another popular bipolar sensor model providing robust operation in the automotive and industrial sectors.
• OH3144: While unipolar, this model is frequently cross-referenced, but requires only a South pole to turn ON and removal of the magnet to turn OFF.

Package Includes:

• 1 x S41 Bipolar Hall Effect Position Sensor (TO-92S)