Diodes AH286 User Manual

AH286

HALL-EFFECT SMART FAN MOTOR CONTROLLER

Description

The AH286 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 AH286 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. A Rotor-lock Detect (RD) output flag allows
external monitoring of any motor locks.

The AH286 is available in SOT89-5L package.

Features

• Single-chip solution

• Operating Voltage: 3.8V to 20V

• Built-in Hall sensor and input amplifier

• Rotor-lock Detect (RD) flag

• Rotor Lock Protection (Lock detection, output shutdown
and automatic re-start)

• Built-in Zener protection for output driver

• Average output current up to 500mA

• Packaged in SOT89-5L

• Green Molding Compound

Pin Assignments

(Top View)

Vdd

1

GND

2

3 7

286

SOT89-5L

RD

5

DOBDO

4

Applications

• Two-coil BLDC cooling fans

• Low to medium voltage, low power BLDC motors

Typical Application Circuit

D2

5 4

286

132

GND

R1
C1

Coil2

Coil1

R2

C2

RD

Vdd

D3

(12V)

D1

C3

R

pu

12V DC Brush-Less Fan with RD Output Function

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.

AH286

Document number: DS31030 Rev. 12 - 2

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Pin Descriptions

Pin Name Description

RD Rotor-state detection

Vdd Input power

DO Output pin
DOB Output pin
GND Ground

Functional Block Diagram

Vdd

AH286

HALL-EFFECT SMART FAN MOTOR CONTROLLER

Lock detect,

shutdown and

automatic re-start

Regulator

Hall

Plate

Amp.

Control Logic

DO

DOB

GND

RD

AH286

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AH286

θJAθ

HALL-EFFECT SMART FAN MOTOR CONTROLLER

Absolute Maximum Ratings (T

Symbol Characteristics Rating Unit

Vdd Supply Voltage 24 V

IO Output Current

PD Power Dissipation 800 mW

TST Storage Temperature -55 ~ 150

TJ Maximum Junction Temperature 150

θ

Thermal Resistance Junction to Case (Note 2) 156

JA

= 25°C)

A

TJ

TA

JC

500 mA

I

O (AVE)

I

O (PEAK)

Tc

700 mA

°C
°C

°C/W

Notes: 2. θJA should be confirmed with heat sink thermal resistance. If there is no heat sink contact, θJA will almost be the same as θJC..

Recommended Operating Conditions

Symbol Characteristic Conditions Min Max Unit

Vdd Supply Voltage Operating 3.8 20 V

TA Operating Ambient Temperature Operating -40 100

°C

AH286

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AH286

HALL-EFFECT SMART FAN MOTOR CONTROLLER

Electrical Characteristics (T

= 25 °C, Vdd = 12V, unless otherwise specified)

A

Symbol Characteristics Conditions Min Typ. Max Unit

Idd Supply Current Operating - 2.0 4.0 mA
I

Output Leakage Current V

OFF

T

RLP-ON

T

RLP-OFF

V

OUT(SAT)

R

DS(ON)

Rotor Lock Protection On Time 0.4 0.5 0.6 Sec
Rotor Lock Protection Off Time 2.4 3 3.6 Sec

Output Saturation Voltage

Output On Resistance IO = 300mA - 1.25 1.67 ohm

= 24V - < 0.1 10 μA

OUT

= 300mA - 375 500

I

O

IO = 500mA - 625 900

VOL RD Output Vds IO = 10mA - 0.5 - V

Vz Output Zener-Breakdown Voltage 35 42 60 V

Truth Table (Note 3)

IN- IN+ CT OUT1 OUT2 RD Mode

H L L H L L Rotating

L H L L H L Rotating

- - H off off H Lockup protection activated

Notes: 3. Latch-type RD output is low during rotor rotation and high when the rotor is locked (not rotating)

mV

Magnetic Characteristics (T

= 25 °C, Vdd = 12V, unless otherwise specified, Note 4)

A

(1mT = 10 Gauss)

Symbol Characteristics Min Typ. Max Unit

Bop Operate Point 10 30 60 Gauss

Brp Release Point -60 -30 -10 Gauss

Bhy Hysteresis - 60 - Gauss

Notes: 4. The magnetic characteristics may vary with supply voltage, operating temperature and after soldering.

AH286

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Operating Characteristics

DOB DO

AH286

HALL-EFFECT SMART FAN MOTOR CONTROLLER

RP

ON

Output Voltage in Volts

12
10
8
6
4
2

OFF

OP

Vsat Vsat

OFF

RP

Output Voltage in Volts

Magnetic Flux Density in GaussMagnetic Flux Density in Gauss

12
10
8
6
4
2

OP

ON

BopBrp 0BopBrp 0

S

Marking

side

AH286

Document number: DS31030 Rev. 12 - 2

N

( SOT89-5L )

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Performance Characteristics

TA (°C)

PD (mW)

TA (°C)

PD (mW)

(mW)

P

D

900
800
700
600
500
400
300
200
100

0

AH286

Document number: DS31030 Rev. 12 - 2

25 50 60 70 75 80 85 90 95 100

800 640 576 512 480 448 416 384 352 320

105 110 115 120 125 130 135 140 145 150

288 256 224 192 160 128 96 64 32 0

-40

0 25 50 75 100 125 150

AH286

HALL-EFFECT SMART FAN MOTOR CONTROLLER

Power Dissipation Curve

TA (°C)

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AH286

HALL-EFFECT SMART FAN MOTOR CONTROLLER

Ordering Information

AH 286 - Y G - 13

PackingPackage Green

Y : SOT89-5L 13 : Tape & ReelG : Green (Note 5)

Device

AH286-YG-13 Y SOT89-5L NA NA 2500/Tape & Reel -13

Notes: 5. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at

http://www.diodes.com/products/lead_free.html.

6. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at
http://www.diodes.com/datasheets/ap02001.pdf.

7. Reverse taping as shown on Diodes Inc. Surface Mount (SMD) Packaging document AP02007, which can be found on our website

http://www.diodes.com/datasheets/ap02007.pdf.

Package

Code

Packaging

(Note 6, 7)

Quantity

Bulk 13” Tape and Reel

Part Number

Suffix

Quantity

Part Number

Suffix

Marking Information

(Top View)

5

4

286 Y W X

1 2 3

SOT89-5L

7

Y : Year : 0~9

: Week : A~Z : 1~26 week;

W

a~z : 27~52 week;

z represents 52 and 53 week

: Internal code

X

A~Z : Green

AH286

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HALL-EFFECT SMART FAN MOTOR CONTROLLER

Package Outline Dimensions (All Dimensions in mm)

AH286

Sensor Location

AH286

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AH286

HALL-EFFECT SMART FAN MOTOR CONTROLLER

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Copyright © 2010, Diodes Incorporated

www.diodes.com

AH286

Document number: DS31030 Rev. 12 - 2

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