Data Sheet
HIGH VOLTAGE HALL EFFECT LATCH
General Description
The AH278 is an integrated Hall sensor with output
driver designed for electronic commutation of brush-
less DC motor applications. The device includes an on-
chip Hall sensor for magnetic sensing, an amplifier
that amplifies the Hall voltage, a Schmitt trigger to
provide switching hysteresis for noise rejection and
two complementary open-collector drivers for sinking
large load current. It also includes an internal band-gap
regulator which is used to provide bias voltage for
internal circuits and allows a wide operating supply
voltage ranges.
Placing the device in a variable magnetic field, if the
magnetic flux density is larger than threshold B
OP
, the
pin DO will be turned low (on) and pin DOB will be
turned high (off). This output state is held until the
magnetic flux density reverses and falls below B
RP,
then causes DO to be turned high (off) and DOB
turned low (on).
AH278 is available in TO-94 (SIP-4L) package.
AH278
Features
·
·
·
·
·
·
·
·
On-Chip Hall Sensor
4V to 30V Supply Voltage
500mA (avg) Output Sink Current
Build in Protection Diode for Reverse Power
Connecting
-20
o
C to 85
o
C Operating Temperature
Low Profile TO-94 (SIP-4L) Package
Build in Over Temperature Protection Function
ESD Rating: 300V(Machine Model)
Applications
·
·
·
·
12V/24V Dual-Coil Brushless DC Motor/Fan
Power Supply and Switchboard
Communications Facilities
Industrial Equipment
TO-94
Figure 1. Package Type of AH278
Nov. 2009 Rev. 1. 4
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BCD Semiconductor Manufacturing Limited
Data Sheet
HIGH VOLTAGE HALL EFFECT LATCH
Functional Block Diagram
V
CC
1
DO
2
AH278
Regulator
Over-Temperature
Protection
4
GND
Hall
Sensor
Amplifier
Schmitt
Trigger
Output
Driver
3
DOB
Figure 3. Functional Block Diagram of AH278
Ordering Information
AH278
Circuit Type
Package
Z4: TO-94 (SIP-4L)
Part Number
Lead Free
AH278Z4-AE1
AH278Z4-BE1
Green
AH278Z4-AG1
AH278Z4-BG1
-
E1: Lead Free
G1: Green
Magnetic Characteristics
A: 10 to 70Gauss
B: 100Gauss
Marking ID
Lead Free
AH278Z4-E1
AH278Z4-E1
Green
AH278Z4-G1
AH278Z4-G1
Packing
Type
Bulk
Bulk
Package
TO-94
Temperature
Range
-20 to 85
o
C
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. 2009 Rev. 1. 4
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BCD Semiconductor Manufacturing Limited
Data Sheet
HIGH VOLTAGE HALL EFFECT LATCH
Absolute Maximum Ratings (Note 1)
(T
A
=25
o
C)
Parameter
Supply Voltage
Reverse Protection Voltage
Magnetic Flux Density
Continuous
Output Current
Hold
Peak (start up)
Power Dissipation
Die to atmosphere
Thermal Resistance
Die to package case
Storage Temperature
ESD (Machine Model)
P
D
θJA
θJC
T
STG
I
O
Symbol
V
CC
V
RCC
B
Value
30
-30
Unlimited
500 (Note 2)
600
800
550
227
49
-50 to 150
300
Unit
V
V
Gauss
mA
mA
mA
mW
o
AH278
C/W
o
C/W
o
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. "Absolute Maximum Ratings" for extended period may affect
device reliability.
Note 2: Continuos output current is 300mA at 85
o
C.
Recommended Operating Conditions
Parameter
Supply Voltage
Operating Ambient Temperature
Symbol
V
CC
T
A
Min
4
-20
Max
28
85
Unit
V
o
C
Nov. 2009 Rev. 1. 4
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BCD Semiconductor Manufacturing Limited
Data Sheet
HIGH VOLTAGE HALL EFFECT LATCH
Electrical Characteristics
(T
A
=25
o
C, V
CC
=24V, unless otherwise specified)
Parameter
Low Supply Voltage
Output Saturation Voltage
Output Saturation Voltage
Output Leakage Current
Supply Current
Output Rise Time
Output Fall Time
Switch Time Differential
Output Zener Breakdown Voltage
Symbol
V
CE
V
SAT
1
V
SAT
2
I
OL
I
CC
tr
tf
∆t
V
ZO
Test Condition
V
CC
=5V, I
O
=100mA
I
O
=500mA
I
O
=300mA
V
DO
,V
DOB
=24V
V
CC
=24V, Output Open
R
L
=820Ω, C
L
=20pF
R
L
=820Ω, C
L
=20pF
R
L
=820Ω, C
L
=20pF
Min
Typ
0.1
0.5
0.25
0.1
12.5
3.0
0.3
3.0
60
Max
0.3
0.8
0.5
10
16
10
1.5
10
Unit
V
V
V
µA
mA
µs
µs
µs
V
AH278
Magnetic Characteristics
(T
A
=25
o
C)
Parameter
Operating Point
Releasing Point
Hysteresis
Symbol
B
OP
B
RP
B
HYS
Grade
A
B
A
B
-70
-100
80
Min
10
Typ
Max
70
100
-10
Unit
Gauss
Gauss
Gauss
Gauss
Gauss
V
DO
(V)
Off-state
High
Turn off
B
HYS
Turn on
V
SAT
On-state
N
B
RP
0
B
OP
Low
S
Magnetic Flux Density (Gauss)
Nov. 2009 Rev. 1. 4
5
BCD Semiconductor Manufacturing Limited
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