AH3781 HIGH-VOLTAGE HIGH-SENSITIVITY HALL EFFECT LATCH WITH INTERNAL PULL-UP RESISTOR Description Pin Assignments The AH3781 is a high-voltage, high-sensitivity Hall Effect latch IC with internal pull-up resistor designed for commutation of brushless (Top View) 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 3 OUTPUT GND 2 optimized to operate over the supply range of 3.0V to 28V. With chopper stabilized architecture and an internal bandgap regulator to 1 V DD provide temperature compensated supply for internal circuits, the AH3781 provides a reliable solution over the whole operating range. SOT23 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) The internally pulled-up output can be switched on with South pole of sufficient strength and switched off with North pole of sufficient 3. OUTPUT strength. When the magnetic flux density (B) perpendicular to the part 2. GND marking surface is larger than the operate point (B ) the output is OP V 1. DD switched on (pulled low). The output is held latched until magnetic flux density reverses and becomes lower than the release point (B ). RP SIP-3 Features Applications Bipolar Latch Operation (South Pole: On, North Pole: off) Brushless DC Motor Commutation 3.0V to 28V Operating Voltage Range Revolution Per Minute (RPM) Measurement High Sensitivity: B and B of +25G and -25G Typical Flow Meters OP RP Internally Pull-up Resistor on the Output Pin Angular and Linear Encoder and Position Sensors Output Overcurrent Limit Contactless Commutation, Speed Measurement and Angular Chopper Stabilized Design Provides Position Sensing/Indexing in Consumer Home Appliances, Office - Superior Temperature Stability Equipments and Industrial Applications - Minimal Switch Point Drift - Enhanced Immunity to Stress Good RF Noise Immunity Zener Clamp on Supply and Output Pins -40C to +125C 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) Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See Low-Pass Filter Sample and Hold Dynamic Offset Cancellation AH3781 Typical Applications Circuit 3.0V to 28V V DD OUTPUT AH3781 C IN GND Note: 4. C is for power stabilization and to strengthen the noise immunity, the recommended capacitance is 10nF ~ 100nF. R is the pull-up resistor. IN L Pin Descriptions Package: SOT23 Pin Number Pin Name Function 1 Power Supply Input V DD 2 GND Ground 3 OUTPUT Output Pin Functional Block Diagram V DD Power switch To All Subcircuits OUTPUT Amp Amp Control Current Limit GND 2 of 13 AH3781 September 2015 Diodes Incorporated www.diodes.com Document number: DS37903 Rev. 1 - 2 PRELIMINARY - CONFIDENTIAL