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.
Pin Assignments
(Top View)
Vdd
1
2
286
5
RD
GND
DO
3
7
DOB
4
SOT89-5L
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
Applications
•
•
Two-coil BLDC cooling fans
Low to medium voltage, low power BLDC motors
Typical Application Circuit
Vdd (12V)
D2
D1 R
pu
RD
5
4
286
1
2
3
Coil2
Coil1
D3
C3
GND
R1
C1
R2
C2
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.
1 of 9
www.diodes.com
June 2010
© Diodes Incorporated
AH286
Document number: DS31030 Rev. 12 - 2
AH286
HALL-EFFECT SMART FAN MOTOR CONTROLLER
Absolute Maximum Ratings
(T
A
= 25°C)
Symbol
Vdd
I
O
P
D
T
ST
T
J
θ
JA
Supply Voltage
Output Current
Power Dissipation
Storage Temperature
Maximum Junction Temperature
Thermal Resistance Junction to Case (Note 2)
T
A
T
J
Tc
Characteristics
I
O (AVE)
I
O (PEAK)
Rating
24
500
700
800
-55 ~ 150
150
156
Unit
V
mA
mA
mW
°C
°C
°C/W
θ
JA
θ
JC
Notes:
2.
θ
JA
should be confirmed with heat sink thermal resistance. If there is no heat sink contact,
θ
JA
will almost be the same as
θ
JC
..
Recommended Operating Conditions
Symbol
Vdd
T
A
Characteristic
Supply Voltage
Operating Ambient Temperature
Conditions
Operating
Operating
Min
3.8
-40
Max
20
100
Unit
V
°C
AH286
Document number: DS31030 Rev. 12 - 2
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© Diodes Incorporated
AH286
HALL-EFFECT SMART FAN MOTOR CONTROLLER
Electrical Characteristics
(T
A
= 25
°C,
Vdd = 12V, unless otherwise specified)
Symbol
Idd
I
OFF
T
RLP-ON
T
RLP-OFF
V
OUT(SAT)
R
DS(ON)
V
OL
Vz
Characteristics
Supply Current
Output Leakage Current
Rotor Lock Protection On Time
Rotor Lock Protection Off Time
Output Saturation Voltage
Output On Resistance
RD Output Vds
Output Zener-Breakdown Voltage
I
O
= 300mA
I
O
= 500mA
I
O
= 300mA
I
O
= 10mA
Conditions
Operating
V
OUT
= 24V
Min
-
-
0.4
2.4
-
-
-
-
35
Typ.
2.0
< 0.1
0.5
3
375
625
1.25
0.5
42
Max
4.0
10
0.6
3.6
500
900
1.67
-
60
Unit
mA
μA
Sec
Sec
mV
ohm
V
V
Truth Table (Note 3)
IN-
IN+
H
L
L
H
-
-
Notes:
CT
L
L
H
OUT1
H
L
off
OUT2
L
H
off
RD
L
L
H
Mode
Rotating
Rotating
Lockup protection activated
3.
Latch-type RD output is low during rotor rotation and high when the rotor is locked (not rotating)
Magnetic Characteristics
(T
A
= 25
°C,
Vdd = 12V, unless otherwise specified, Note 4)
(1mT = 10 Gauss)
Symbol
Bop
Brp
Bhy
Notes:
Characteristics
Operate Point
Release Point
Hysteresis
Min
10
-60
-
Typ.
30
-30
60
Max
60
-10
-
Unit
Gauss
Gauss
Gauss
4. The magnetic characteristics may vary with supply voltage, operating temperature and after soldering.
AH286
Document number: DS31030 Rev. 12 - 2
4 of 9
www.diodes.com
June 2010
© Diodes Incorporated
AH286
HALL-EFFECT SMART FAN MOTOR CONTROLLER
Operating Characteristics
DOB
DO
Output Voltage in Volts
RP
12
10
8
6
4
Output Voltage in Volts
OFF
OFF
12
10
8
6
4
OP
ON
2
OP
Vsat
RP
2
ON
Vsat
Brp
0
Bop
Brp
0
Bop
Magnetic Flux Density in Gauss
Magnetic Flux Density in Gauss
S
Marking
side
N
( SOT89-5L )
AH286
Document number: DS31030 Rev. 12 - 2
5 of 9
www.diodes.com
June 2010
© Diodes Incorporated
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