Description
AH3781
HIGH-VOLTAGE HIGH-SENSITIVITY HALL EFFECT LATCH
WITH INTERNAL PULL-UP RESISTOR
Pin Assignments
The AH3781 is a high-voltage, high-sensitivity Hall Effect latch IC
with internal pull-up resistor designed for commutation of brushless
DC motors, flow meters, linear encoders and position sensors in
industrial, consumer home appliance and personal care applications.
To support a wide range of demanding applications, the design is
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 Zener clamp on the
supply. The output has an overcurrent limit and a Zener clamp.
(Top View)
GND 2
3 OUTPUT
1 VDD
SOT23
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).
(Top View)
SIP-3
3. OUTPUT
2. GND
1. VDD
Features
• Bipolar Latch Operation (South Pole: On, North Pole: off)
• 3.0V to 28V Operating Voltage Range
• High Sensitivity: BOP and BRP of +25G and -25G Typical
• Internally Pull-up Resistor on the Output Pin
• Output Overcurrent Limit
• Chopper Stabilized Design Provides
- Superior Temperature Stability
- Minimal Switch Point Drift
- Enhanced Immunity to Stress
• Good RF Noise Immunity
• Zener Clamp on Supply and Output Pins
• -40°C to +125°C Operating Temperature
• ESD (HBM): 6kV
• Industry Standard SOT23 and SIP-3 Packages
• Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
• Halogen and Antimony Free. “Green” Device (Note 3)
Applications
• Brushless DC Motor Commutation
• Revolution Per Minute (RPM) Measurement
• Flow Meters
• Angular and Linear Encoder and Position Sensors
• Contactless Commutation, Speed Measurement and Angular
Position Sensing/Indexing in Consumer Home Appliances, Office
Equipments and Industrial Applications
Notes:
1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green"
and Lead-free.
3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and
<1000ppm antimony compounds.
AH3781
Document number: DS37903 Rev. 1 - 2
1 of 13
www.diodes.com
September 2015
© Diodes Incorporated
