Hall Effect Sensor A3144
 

The A3144 is an integrated Hall effect nonlatching sensor. That's nice but what does it do? Holding a magnet near the sensor will cause the output pin to toggle. This makes for a robust presence sensor. A reed sensor also works nicely, but can be limited by the glass encapsulation and size. A hall effect sensor is much smaller, but can handle less current than a reed switch.The device includes an on-chip Hall voltage generator for magnetic sensing, a comparator that amplifies the Hall voltage, and a Schmitt trigger to provide switching hysteresis for noise rejection, and open-collector output. An internal bandgap regulator is used to provide temperature compensated supply voltage for internal circuits and allows a wide operating supply range.If a magnetic flux density larger than threshold Bop, DO is turned on (low). The output state is held until a magnetic flux density reversal falls below Brp causing DO to be turned off (high).
 

Features

• Superior Temp. Stability for Automotive or Industrial Applications
• 4.5 V to 24 V Operation … Needs Only An Unregulated Supply
• Open-Collector 25 mA Output … Compatible with Digital Logic
• Reverse Battery Protection
• Activate with Small, Commercially Available Permanent Magnets
• Solid-State Reliability 
•  Small Size
• Resistant to Physical Stress