AH3774
HIGH-VOLTAGE HIGH-SENSITIVITY HALL EFFECT LATCH
Description Pin Assignments
The AH3774 is a high-voltage, high-sensitivity Hall Effect Latch IC
designed for commutation of brushless DC motor, flow meters, linear
encoders and position sensors in industrial and consumer home
(Top View)
appliance and personal care applications. To support a wide range of
demanding applications, the design is optimized to operate over the
3 OUTPUT
supply range of 3.0V to 28V. With chopper stabilized architecture and
GND 2
an internal bandgap regulator to provide temperature compensated
1 V
DD
supply for internal circuits, the AH3774 provides a reliable solution
over the whole operating range. For robustness and protection, the
SC59 and SOT23
device has a reverse blocking diode with a Zener clamp on the
supply. The output has an over current limit and a Zener clamp.
The single open-drain 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
package is larger than the operate point (Bop) the output is switched
(Top View)
on (pulled low). The output is held latched until magnetic flux density
3. OUTPUT
reverses and becomes lower than the release point (Brp).
2. GND
The magnetic operating and release polarity is opposite for SOT23
V
1. DD
and SC59 packages. SOT23 and SIP-3 packages will require South
SIP-3
Pole to the part marking side to operate while SC59 will require South
Pole to the non-part marking side.
Features Applications
Bipolar Latch (South Pole: On, North Pole: Off) Brushless DC Motor Commutation
3.0V to 28V Operating Voltage Range Revolution Per Minute (RPM) Measurement
High Sensitivity: Bop and Brp of +40G and -40G Typical Flow Meters
Single Open Drain Output with Over Current Limit Angular and Linear Encoder and Position Sensors
Chopper Stabilized Design Provides Contact-less Commutation, Speed Measurement and Angular
Superior Temperature Stability Position Sensing/Indexing in Consumer Home Appliances, Office
Minimal Switch Point Drift Equipments and Industrial Applications
Enhanced Immunity to Stress
Good RF Noise Immunity
Reverse Blocking Diode and Zener Clamp on Supply
-40C to +125C Operating Temperature
ESD (HBM): 6kV
Industry Standard SC59, 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
AH3774
Typical Applications Circuit
3.0V to 28V
V
DD
R
L
OUTPUT
AH3774
C
IN
GND
Note: 4. C is for power stabilization and to strengthen the noise immunity, the recommended capacitance is 10nF ~ 100nF.
IN
R is the pull-up resistor.
L
Pin Descriptions
Package: SC59, SOT23 and SOT23
Pin Number Pin Name Function
1 V Power Supply Input
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 14
AH3774 September 2015
Diodes Incorporated
www.diodes.com
Document number: DS37899 Rev. 1 - 2