
Data Sheet
COMPLEMENTARY OUTPUT HALL EFFECT LATCH AH277A
General Description
The AH277A is an integrated Hall sensor with output
driver designed for electronic commutation of brushless DC motor applications. The device includes an onchip Hall sensor for magnetic sensing, an amplifier
that amplifies the Hall voltage, a Schmitt trigger to
provide switching hysteresis for noise rejection, a temperature compensation circuit to compensate the temperature drift of Hall sensitivity 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.
Placing the device in a variable magnetic field, if the
magnetic flux density is larger than threshold B
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
then causes DO to be turned high (off) and DOB
turned low (on).
AH277A is available in TO-94 (SIP-4L) package.
OP
, the
RP,
Features
· On-Chip Hall Sensor
· 3.5V to 16V Supply Voltage
· 400mA (avg) Output Sink Current
· Reversed Supply Voltage Protection
o
· -20
· Low Profile TO-94 (SIP-4L) Package
· ESD Rating: 300V (Machine Model)
C to 85oC Operating Temperature
Applications
· Dual-Coil Brushless DC Motor
· Dual-Coil Brushless DC Fan
· Revolution Counting
· Speed Measurement
TO-94
Figure 1. Package Type of AH277A
Oct. 2009 Rev. 1. 6 BCD Semiconductor Manufacturing Limited
1

Data Sheet
COMPLEMENTARY OUTPUT HALL EFFECT LATCH AH277A
Pin Configuration
Z4 Package
(TO-94)
Pin Description
Pin Number Pin Name Function
1
2 DO Output 1
3 DOB Output 2
4 GND Ground
4
3
2
1
Figure 2. Pin Configuration of AH277A (Front View)
V
CC
Supply voltage
GND
DOB
DO
V
CC
Oct. 2009 Rev. 1. 6 BCD Semiconductor Manufacturing Limited
2

Data Sheet
COMPLEMENTARY OUTPUT HALL EFFECT LATCH AH277A
Functional Block Diagram
V
CC
1
Regulator
Temperature
Compensation
DO
2
4
GND
Hall
Sensor
Ordering Information
Circuit Type
Package
Z4: TO-94 (SIP-4L)
Amplifier
Figure 3. Functional Block Diagram of AH277A
Schmitt
Trigger
Output
Driver
AH277A -
E1: Lead Free
G1: Green
Magnetic Characteristics
A: 10 to 50Gauss
B: 5 to 70Gauss
C: 100Gauss
3
DOB
Package
TO-94
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.
Temperature
Range
-20 to 85
o
C
Lead Free Green Lead Free Green
AH277AZ4-AE1 AH277AZ4-AG1 AH277A AH277A-G1 Bulk
AH277AZ4-BE1 AH277AZ4-BG1 AH277A AH277A-G1 Bulk
AH277AZ4-CE1 AH277AZ4-CG1 AH277A AH277A-G1 Bulk
Part Number Marking ID
Packing
Typ e
Oct. 2009 Rev. 1. 6 BCD Semiconductor Manufacturing Limited
3

Data Sheet
COMPLEMENTARY OUTPUT HALL EFFECT LATCH AH277A
Absolute Maximum Ratings (Note 1)
(T
=25oC)
A
Parameter Symbol Value Unit
Supply Voltage V
Reverse Protection Voltage V
CC
RCC
20 V
-20 V
Magnetic Flux Density B Unlimited Gauss
Output Current
Continuous
Hold 600 mA
I
O
400 mA
Peak (start up) 800 mA
Power Dissipation P
Die to atmosphere θJA 227
D
550 mW
o
C/W
Thermal Resistance
Die to package case θJC 49
Storage Temperature T
STG
-50 to 150
o
C/W
o
C
ESD (Machine Model) 300 V
ESD (Human Body Model) 2000 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
(TA=25oC)
Parameter Symbol Min Max Unit
Supply Voltage
Ambient Temperature
V
CC
T
A
Oct. 2009 Rev. 1. 6 BCD Semiconductor Manufacturing Limited
4
3.5 16 V
-20 85
o
C

Data Sheet
COMPLEMENTARY OUTPUT HALL EFFECT LATCH AH277A
Electrical Characteristics
(TA=25oC, VCC=14V, unless otherwise specified)
Parameter Symbol Test Condition Min Typ Max Unit
Output Saturation Voltage
Output Leakage Current I
Supply Current I
V
OL
CC
Output Rise Time tr R
Output Fall Time tf R
Switch Time Differential ∆tR
Output Zener Breakdown Voltage V
VCC=3.5V, IO=100mA 0.4 V
SAT
I
=400mA
O
VCE=16V
VCC=16V, Output Open
=820Ω, CL=20pF
L
=820Ω, CL=20pF
L
=820Ω, CL=20pF
L
Z
0.35 0.6 V
0.1 10
12 16 mA
3.0 10
0.3 1.5
3.0 10
55 V
µA
µs
µs
µs
Magnetic Characteristics
(TA=25oC)
Parameter Symbol Grade Min Typ Max Unit
A103050Gauss
Operating Point
Releasing Point
Hysteresis B
B
B
OP
RP
HYS
B 5 70 Gauss
C 100 Gauss
A -50 -30 -10 Gauss
B -70 -5 Gauss
C -100 Gauss
60 Gauss
VDO (V)
Off-state
High
B
Turn off Turn on
V
SAT
HYS
Low
On-state
B
RP
0
B
OP
SN
Magnetic Flux Density (Gauss)
Oct. 2009 Rev. 1. 6 BCD Semiconductor Manufacturing Limited
5

Data Sheet
COMPLEMENTARY OUTPUT HALL EFFECT LATCH AH277A
Magnetic Characteristics (Continued)
S
Marking Side
N
DO (V)
V
CC
-40 -20 0 20 40
Magnetic Flux Density B (Gauss)
16
14
12
10
8
6
4
2
+14V
V
12
R1
820Ω
R2
820Ω
Figure 4. Basic Test Circuit
V
SAT
V
SAT
-40 -20 0 20 40
AH277A
CC
DO DOB GND
4
3
C1 C2
20pF 20pF
DOB (V)
16
14
12
10
8
6
4
2
Magnetic Flux Density B (Gauss)
DO (V
DOB (V
OUT1
V
CC
OUT2
)
)
Figure 5. V
vs. Magnetic Flux Density
DO
Figure 6. V
vs. Magnetic Flux Density
DOB
Oct. 2009 Rev. 1. 6 BCD Semiconductor Manufacturing Limited
6

Data Sheet
COMPLEMENTARY OUTPUT HALL EFFECT LATCH AH277A
Typical Performance Characteristics
14
12
10
8
(mA)
CC
6
I
4
2
0
0 5 10 15 20 25
T
= -20oC
A
T
= 0oC
A
T
=25oC
A
T
=80oC
A
VCC (V)
Figure 7. I
CC
vs. V
CC
60
50
40
30
(Gauss)
20
HY
, B
RP
, B
OP
B
-10
-20
-30
B
10
0
OP
B
RP
B
HYS
0 5 10 15 20 25
VCC (V)
Figure 8. B
OP/BRP/BHYS
vs. V
CC
60
50
40
30
(Gauss)
20
HYS
, B
10
RP
, B
0
OP
B
-10
-20
-20-100 102030405060708090100110
B
OP
B
RP
B
HYS
TA (oC)
Figure 9. BOP/BRP/B
vs. Ambient Temperature
HYS
800
600
400
(mW)
D
P
200
0
-25 0 25 50 75 100 125 150
TA (oC)
Figure 10. PD vs. Ambient Temperature
Oct. 2009 Rev. 1. 6 BCD Semiconductor Manufacturing Limited
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Data Sheet
COMPLEMENTARY OUTPUT HALL EFFECT LATCH AH277A
Typical Performance Characteristics (Continued)
14
12
10
(mA)
CC
I
8
6
VCC=3.5V
VCC=14V
VCC=20V
-20 0 20 40 60 80
TA (oC)
600
550
500
450
400
(mV)
SAT
V
350
300
250
200
IO=300mA
IO=350mA
IO=400mA
V
=14V
CC
-20 0 20 40 60 80
TA (oC)
Figure 11. Supply Current vs. Ambient Temperature Figure 12. Saturation Voltage vs. Ambient Temperature
Typical Applications
D1
AH277A
COIL1 COIL2
V
CC
DO DOB GND
12
V
CC
4
3
R1
470
C1
2.2µF
++
R2
470
C2
2.2µF
Figure 13. Typical Application Circuit with D1(Note 2)
Note 2: AH277A has Reversed Supply Voltage Protection. For DC fan application, sometimes need to test power
reverse connection condition. The internal diode only protects chip-side but not for coil-side. It is recommended to
add one external diode D1 in application to block the reverse current from coil-side as shown in Figure 13.
Oct. 2009 Rev. 1. 6 BCD Semiconductor Manufacturing Limited
8

BCD Semiconductor Manufacturing Limited
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cations herein. BCD Semiconductor Manufacturing Limited does not assume any responsibility for use of any its products for any
cations herein. BCD Semiconductor Manufacturing Limited does not assume any responsibility for use of any its products for any
particular purpose, nor does BCD Semiconductor Manufacturing Limited assume any liability arising out of the application or use
particular purpose, nor does BCD Semiconductor Manufacturing Limited assume any liability arising out of the application or use
of any its products or circuits. BCD Semiconductor Manufacturing Limited does not convey any license under its patent rights or
of any its products or circuits. BCD Semiconductor Manufacturing Limited does not convey any license under its patent rights or
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