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High Voltage High Sensitivity Hall Effect Latch with Supply and Output Pin Clamp, Reverse Voltage Protection and Current Limit


The AH3781 is a high voltage high sensitivity Hall Effect latch IC with internal pull-up resistor designed for commutation of brushless DC motor, flow meters, linear encoders and position sensors in industrial and consumer home appliance and personal care applications. To support wide range of demanding applications, the design has been optimized to operate over the supply range of 3.0V to 28V. With chopper stabilized architecture and an internal bandgap regulator to provide temperature compensated supply for internal circuits, the AH3781 provides a reliable solution over the whole operating range. For robustness and protection, the device has a reverse blocking diode with a Zener clamp on the supply. The output has a current limit and a Zener clamp.

The internally pulled-up output can be switched on with South pole of sufficient strength and switched off with North pole of sufficient strength. When the magnetic flux density (B) perpendicular to the part marking surface is larger than the operate point (Bop) the output is switched on (pulled low). The output is held latched until magnetic flux density reverses and becomes lower than the release point (Brp).

The AH3781 is available in industry standard SOT23 and SIP-3 packages.


  • Brushless DC Motor Commutation
  • Revolution Per Minute (RPM) Measurement
  • Flow Meters
  • Angular and Linear Encoder and Position Sensors
  • Contact-less Commutation, Speed Measurement and Angular Position Sensing/Indexing in Consumer Home Appliances, Office Equipments and Industrial Applications


  • Bipolar Latch Operation (South Pole: On, North Pole: off)
  • 3.0V to 28V Operating Voltage Range
  • High Sensitivity: Bop and Brp of +25Gand -25G typical
  • Single Open Drain Output with Current Limit
  • Chopper Stabilized Design Provides
  • Superior Temperature Stability
  • Minimal Switch Point Drift
  • Enhanced Immunity to Stress
  • Good RF Noise Immunity
  • Reverse Blocking Diode and Zener Clamp on Supply
  • -40°C to 125°C Operating Temperature
  • ESD (HBM) > 6kV
  • Industry Standard SOT23 and SIP-3 Packages
  • Totally Lead-Free & Fully RoHS Compliant
  • Halogen and Antimony Free. “Green” Device

Product Specifications

Product Parameters

Qualified to AECQ10x No
Automotive Compliant PPAP No
Output Type Single, Internal Pull-Up Resistor, Active Low
Operating Voltage 3 to 28 V
Average Supply Current 3.8 mA
Output Current Capability 30 mA
Grade -
Operating Point Bop (Bops +ve/ Bopn -ve) Gauss (Min) 10
Operating Point Bop (Bops +ve/ Bopn -ve) Gauss (Typ) 25
Operating Point Bop (Bops +ve/ Bopn -ve) Gauss (Max) 40
Release Point Brp (Brps +ve/Brpn -ve) Gauss (Min) -40
Release Point Brp (Brps +ve/Brpn -ve) Gauss (Typ) -25
Release Point Brp (Brps +ve/Brpn -ve) Gauss (Max) -10
Operating Ambient Temperature -40 to 125 °C

Related Content

SIP-3 (Ammo)
SIP-3 (Bulk)


Quality & Reliability

Technical Documents

Recommended Soldering Techniques
Orderable Part Number Authorized Distributor Quantity Inventory Date Buy Online Region
AH3781-P-A Arrow Electronics 950 7/22/2019 Buy Now Americas
AH3781-P-A Mouser Electronics Inc. 3592 7/22/2019 Buy Now Americas
AH3781-P-B Arrow Electronics 950 7/22/2019 Buy Now Americas
AH3781-P-B Digi-Key Electronics 910 7/22/2019 Buy Now Americas
AH3781-P-B Mouser Electronics Inc. 896 7/22/2019 Buy Now Americas
AH3781-SA-7 Arrow Electronics 720 7/22/2019 Buy Now Americas
AH3781-SA-7 Digi-Key Electronics 2275 7/22/2019 Buy Now Americas
AH3781-SA-7 Mouser Electronics Inc. 1998 7/22/2019 Buy Now Americas