Data Sheet
SINGLE PHASE HALL EFFECT LATCH WITH LOCKED PROTECTION
General Description
The AH478 is a single coil Hall sensor with output
drivers designed for brush-less DC motor application.
This IC consists of one H-bridge driver for motor's coil
driving and has automatic lock shutdown and restart
function relatively. To avoid coil burning, rotor lock
shutdown detection circuit shut down the output driver
if the rotor is blocked and then the automatic recovery
circuit will try to restart the motor. This function
repeats while rotor is blocked. Until the blocking is
removed, the motor recovers running normally.
If a magnetic flux density is larger than threshold B
OP
,
the DO is turned to sink and DOB is turned to drive.
This output state is held until a magnetic flux density
reversal falls below B
RP,
causing DO to be turned to
drive and DOB turned to sink.
This IC is available in TO-95 package.
AH478
Features
·
·
·
·
·
·
·
·
·
·
·
On-chip Hall Sensor
Rotor-locked Shutdown
Automatically Restart
Operating Voltage: 3.5 to 18V
High Output Sourcing/Sinking Capability up to
300mA
Bi-direction H-type Output Drivers for Single
Coil
Internal Bandgap Regulator for Temperature
Compensation
Low Output Switching Current Noise
Operating Temperature: -20 to 85
o
C
Low Profile TO-95 Package
ESD Rating: 3000V (Human Body Model)
Applications
·
·
Single Coil Brushless DC Motor
Single Coil Brushless DC Fan
TO-95
Figure 1. Package Type of AH478
Nov. 2008 Rev. 1. 2
1
BCD Semiconductor Manufacturing Limited
Data Sheet
SINGLE PHASE HALL EFFECT LATCH WITH LOCKED PROTECTION
Functional Block Diagram
V
CC
2
Regulator
4
DOB
V
CC
AH478
Hall
Sensor
Amplifier
Schmitt
Trigger
Pre-
driver
V
CC
3
DO
Lock
Protection and
Auto Restart
1
CT
5
GND
Figure 3. Functional Block Diagram of AH478
Ordering Information
AH478
Circuit Type
Package
Z5: TO-95
-
E1: Lead Free
G1: Green
Magnetic Characteristics
A: 5 to 70 Gauss
B: 100 Gauss
Part Number
Lead Free
AH478Z5-AE1
AH478Z5-BE1
Green
AH478Z5-AG1
AH478Z5-BG1
Marking ID
Lead Free
AH478Z5-E1
AH478Z5-E1
Green
AH478Z5-G1
AH478Z5-G1
Package
TO-95
Temperature
Range
-20 to 85
o
C
Packing Type
Bulk
Bulk
BCD Semiconductor's Pb-free products, as designated with "E1" suffix in the part number, are RoHS compliant. Products with
"G1" suffix are available in green package.
Nov. 2008 Rev. 1. 2
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BCD Semiconductor Manufacturing Limited
Data Sheet
SINGLE PHASE HALL EFFECT LATCH WITH LOCKED PROTECTION
Absolute Maximum Ratings (Note 1)
(T
A
=25
o
C)
Parameter
Supply Voltage
Magnetic Flux Density
Continuous
Output ON Current
Hold
Peak (start up)
Power Dissipation
Thermal Resistance
Storage Temperature
ESD (Machine Model)
ESD (Human Body Model)
Die to atmosphere
P
D
θ
JA
T
STG
I
OUT
Symbol
V
CC
B
Value
20
Unlimited
250
300
600
600
208
-50 to 150
300
3000
Unit
V
Gauss
mA
mA
mA
mW
o
C/W
o
AH478
C
V
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. "Absolute Maximum Ratings" for extended period may affect
device reliability.
Recommended Operating Conditions
(T
A
=25
o
C)
Parameter
Supply Voltage
Ambient Temperature
Symbol
V
CC
T
A
Min
3.5
-20
Max
18
85
Unit
V
o
C
Nov. 2008 Rev. 1. 2
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BCD Semiconductor Manufacturing Limited
Data Sheet
SINGLE PHASE HALL EFFECT LATCH WITH LOCKED PROTECTION
Electrical Characteristics
(T
A
=25
o
C, V
CC
=14V, unless otherwise specified)
Parameter
Output Saturation Voltage (Sink)
Output Saturation Voltage (Drive)
Supply Current
Output ON Time
Output OFF Time
Charge Current
Discharge Current
Duty Ratio
Clamp Voltage
Comparator Voltage
Thermal Resistance (Junction to Case)
V
SAT
I
CC
T
ON
T
OFF
I
CHG
I
DHG
D
R
V
CL
V
CP
θ
JC
Symbol
Test Condition
I
OUT
=150mA
I
OUT
=150mA
V
CC
=20V, output open
R
L
=820Ω, C
CT
=0.47µF
R
L
=820Ω, C
CT
=0.47µF
V
CT
=1 to 2.5V
V
CT
=3.5 to 2.5V
T
OFF
/T
ON
Limiting Voltage
Limiting Voltage
TO-95
5
V
CC
-
1.0
Min
Typ
0.2
V
CC
-
0.8
14
135
1
3.5
0.5
7
2.8
1.8
45
o
AH478
Max
0.25
V
CC
16
Unit
V
V
mA
ms
s
µA
µA
10
V
V
C/W
Magnetic Characteristics
(T
A
=25
o
C)
Parameter
Operating Point
Symbol
B
OP
B
A
Releasing Point
Hysteresis
B
RP
B
B
HYS
-100
70
Gauss
-70
100
-5
Gauss
Grade
A
Min
5
Typ
Max
70
Gauss
Unit
Test Circuit
AH478
S
Marking Side
1
Power
Input
C
1
10
µF
C
CT
2.2µ F
(Front View)
CT V
CC
DO DOB GND
2
3
4
5
R
L
820
Ω
N
Nov. 2008 Rev. 1. 2
5
BCD Semiconductor Manufacturing Limited
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