Data Sheet
TWO PHASE DUAL-COIL CMOS SMART FAN MOTOR DRIVER AH9279
General Description Features
The AH9279 is a most advanced fan control and On Chip Hall Sensor
drive Hall IC manufactured by special CMOS Built-in Zener Diodes Protection for Output
process. This IC consists of voltage reference, Hall Driver
sensor, signal amplifier, wave shaping circuit, locked Power Efficient CMOS and Power MOSFET
rotor detector, locked rotor protection and restart Drivers Allow 400mA Without Overheating
circuit, output drive circuit, etc.. To allow survival in 5V and 12V Operation
a harsh environment and in consideration of low cost, High Sensitivity for Switching Symmetry
the AH9279 has been designed with many functions Locked Rotor Shutdown and Auto Restart
internally, and requires less external components. ESD Rating: 4000V(Human Body Model)
400V(Machine Model)
When there is no motion for one second, the IC will
detect locked rotor conditions, enter protection mode
automatically and disable two outputs for five
seconds. Then, it will turn on drive current from one Applications
channel for one second. If it still fails to detect fan
rotation, the AH9279 will shut off the outputs for five Dual-coil Brushless DC Fan
seconds again. This sequence will be repeated until
rotation condition is detected and the IC enters
normal operation mode. This function prevents the
chip from overheating and damage due to long time
locked rotor.
The power dissipation decides allowable maximum
ambient temperature. Low power dissipation of
AH9279 and the output MOSFET power transistor
enable it to be used at ambient temperature up to
125 C on condition that the drive power is lower than
100mW or drive current is less than 200mA.
The AH9279 is available in TO-94 package.
TO-94
Figure 1. Package Type of AH9279
Oct. 2011 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
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Data Sheet
TWO PHASE DUAL-COIL CMOS SMART FAN MOTOR DRIVER AH9279
Pin Configuration
Z4 Package
(TO-94)
4 GND
3 DOB
2 DO
VCC
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Figure 2. Pin Configuration of AH9279 (Front View)
Pin Description
Pin Number Pin Name Function
1 VCC Power supply pin
2 DO Output pin 1
3 DOB Output pin 2
4 GND Ground pin
Oct. 2011 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
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