Diodes AH9279 User Manual

TWO PHASE DUAL-COIL CMOS SMART FAN MOTOR DRIVER AH9279

Data Sheet

General Description

The AH9279 is a most advanced fan control and drive Hall IC manufactured by special CMOS process. This IC consists of voltage reference, Hall sensor, signal amplifier, wave shaping circuit, locked rotor detector, locked rotor protection and restart circuit, output drive circuit, etc.. To allow survival in a harsh environment and in consideration of low cost, the AH9279 has been designed with many functions internally, and requires less external components.

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 channel for one second. If it still fails to detect fan rotation, the AH9279 will shut off the outputs for five 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 MOS 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.

FET power transistor

Features

• On Chip Hall Sensor

• Built-in Zener Diodes Protection for Output Driver

• Power Efficient CMOS and Power MOSFET Drivers Allow 400mA Without Overheating

• 5V and 12V Operation

• High Sensitivity for Switching Symmetry

• Locked Rotor Shutdown and Auto Restart

• ESD Rating: 4000V(Human Body Model)

400V(Machine Model)

Applications

• Dual-coil Brushless DC Fan

Figure 1. Package Type of AH9279

TO-94

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 3 2 1

Figure 2. Pin Configuration of AH9279 (Front View)

GND

DOB

DO

VCC

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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Data Sheet

TWO PHASE DUAL-COIL CMOS SMART FAN MOTOR DRIVER AH9279

Functional Block Diagram

Figure 3. Functional Block Diagram of AH9279

Ordering Information

AH9279 -

Circuit Type

Package Z4: TO-94

Package Temperature Range Part Number Marking ID Packing Type

TO-94

BCD Semiconductor's Pb-free products, as designated with "G1" suffix in the part number, are RoHS compliant and green.

-20 to 125°C

AH9279Z4-G1 9279Z4-G1 Bulk

G1: Green

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

Absolute Maximum Ratings (TA=25°C, Note 1)

Parameter Symbol Value Unit

Supply Voltage

Supply current (Fault)

Output current

Power dissipation

Thermal Resistance (Junction to Ambient) θJA 227

Storage Temperature T

ESD (Human Body Model) ESD

ESD (Machine Model) ESD

V

I

CC

OUT

P

STG

D

18 V

5 mA

500 mA

550 mW

°C/W

-55 to 150

4000

400

°C

V

Note 1: Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “Recommended Operating Conditions” is not implied. Exposure to “Absolute Maximum Ratings” for extended periods may affect device reliability.

Recommended Operating Conditions

Parameter Symbol Min Max Unit

Supply Voltage VCC 3.5 16 V

Ambient Temperature TA -20 125

°C

Oct. 2011 Rev. 1. 3 BCD Semiconductor Manufacturing Limited

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