Diodes AH284 - Manual

AH284
HALL-EFFECT SMART FAN MOTOR CONTROLLER
AH284
Document number: DS31051 Rev. 11 - 2
1 of 10
www.diodes.com
June 2010
© Diodes Incorporated
Description
The AH284 is a single-chip solution for driving two-coil
brushless direct current (BLDC) fans and motors. The device
includes a Hall-effect sensor, dynamic offset correction and
two complementary open-drain output drivers with internal
Zener diode protection.
To help protect the motor coils, the AH284 provides Rotor
Lock Protection which shuts down output drives if rotor lock is
detected. The device automatically re-starts when the rotor
lock is removed.
The AH284 is available in SIP4 and SOT89-5L packages.
Features
• Single-chip solution
• Operating Voltage: 3.8V to 20V
• Built-in Hall sensor and input amplifier
• Rotor Lock Protection (Lock detection, output shutdown
and automatic re-start)
• Built-in Zener protection for output driver
• Average output current up to 500mA
• Packages: SIP-4L and SOT89-5L
• Green Molding Compound
Pin Assignments
284
1 2 4 3
1 : Vdd
2 : DO
3 : DOB
4 : GND
SIP-4L
(Top View)
1
2
3 74
5
DOB DO
GND
NC Vdd
SOT89-5L
284
(Top View)
Applications
• Two-coil BLDC cooling fans
• Low to medium voltage, low power BLDC motors
Typical Application Circuit (Note 1)
V
dd
DOB
GND
12V D2
L2 L1
284
1 2 3 4
D1
R1 R2
C1 C2
D3
DO
C3
Notes: 1. Typically it is recommended to us a 56 Ohm resistor for R1 and R2 and a 2.2 μF E-Cap capacitor for C1, C2 and C3. These values
may need to be optimized depending on the coils used.
To help with IC protection it’s advised to add a Zener diode between Vdd and ground. The Zener diode should be chosen to help
prevent the supply voltage exceeding the maximum rating of the device.