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Diodes Incorporated |
AH284
HALL-EFFECT SMART FAN MOTOR CONTROLLER
Description
Pin Assignments
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.
(Top View)
(Top View)
284 Vdd 1
1 : Vdd
5 NC
2 : DO GND 2
284
12 3 4
SIP-4L
3 : DOB
4 : GND
DO 3
74 DOB
SOT89-5L
Features
Applications
• 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
• Two-coil BLDC cooling fans
• Low to medium voltage, low power BLDC motors
Typical Application Circuit (Note 1)
12V Vdd D2
D1 284
L2 L1
1234
GND
D3 C3
DO
DOB
R1
C1
R2
C2
Notes:
1. Typically it is recommended to us a 56 Ohm resistor for R1 and R2 and a 2.2μF 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.
AH284
Document number: DS31051 Rev. 11 - 2
1 of 10
www.diodes.com
June 2010
© Diodes Incorporated
Pin Descriptions
Pin Name
Vdd
DO
DOB
GND
NC
Description
Input Power
Output Pin
Output Pin
Ground
Not Connected
Functional Block Diagram
Vdd
Regulator
Hall
Plate
Amp.
AH284
HALL-EFFECT SMART FAN MOTOR CONTROLLER
Lock detect,
shutdown and
automatic re-start
Control Logic
DO
DOB
GND
AH284
Document number: DS31051 Rev. 11 - 2
2 of 10
www.diodes.com
June 2010
© Diodes Incorporated
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