Description
The A3144E is a unipolar digital Hall effect sensor switch designed for non-contact magnetic field detection. It integrates a Hall voltage generator, voltage regulator, temperature compensation circuit, small-signal amplifier, Schmitt trigger, and open-collector output in a single 3-pin package . The sensor responds to the South pole of a magnet: when the magnetic flux density exceeds the operate point (Bop), the output pulls LOW; when the flux falls below the release point (Brp), the output returns HIGH via a pull-up resistor .
The device is widely used for brushless motor commutation, speed sensing, position detection, and proximity switching . The E-suffix indicates the extended temperature range. For the original Allegro part, this is -40°C to +85°C . For the current JSMSEMI production part, the range extends to -40°C to +125°C with a 3.8V–40V supply .
Critical limitations: The output is open-collector—a pull-up resistor (internal or external 10kΩ) is mandatory . The sensor is unipolar: it responds to the South pole only; the North pole does not trigger it . Do not assume the “Original” designation applies to your stock—verify the manufacturer (Allegro vs. JSMSEMI) before publishing.
Features
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Unipolar Operation: Triggers on South magnetic pole; releases when the magnet is removed .
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Open-Collector Output: Sinks up to 25mA (Allegro) or 30mA (JSMSEMI); requires a pull-up resistor .
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Wide Supply Voltage: 4.5V–24V (Allegro original) or 3.8V–40V (JSMSEMI production) .
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Digital Output with Schmitt Trigger: Built-in hysteresis (typically 20–55 Gauss) ensures clean switching without noise-induced false triggers .
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Reverse Polarity Protection: Built-in protection against supply reversal .
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Fast Switching: Suitable for RPM and pulse counting applications.
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TO-92S Package: 3-pin through-hole for easy breadboard and PCB mounting.
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A3144-Compatible Replacement: Functions as a drop-in for the widely used A3144 series.







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