AK8776

[AK8776]
AK8776
Hall IC for Pulse Encoder
Overview
AK8776 is a Hall effect latch which detects both “vertical” and “horizontal” (perpendicular and parallel to the
marking side of the package) magnetic field at the same time and outputs the pulse (F) and rotational direction (D).
AK8776 is for use in portable devices which uses rotational detection system or incremental pulse encoder such as
jog dial utilized for input devices.
Features
o
1.6 to 5.5V operation
o
Bop, Brp(Vertical, Horizontal) ±1.5mT(Typ.), Highly sensitive
o
Low power operation : Average 90μA(Typ.) @VDD=3V
o
Two Output: F-Output (Pulse count), D-Output (Direction of rotation)
o
Small package: SOP-4pin, Halogen free
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Block Diagram
VDD
BIAS
OSC
HE_DRIVE
TIMING LOGIC
VSS
CHOP_AMP
COMP
LATCH&LOGIC
CHOPPER_SW
HALL SENSORS
F
D
Figure 1. Block diagram
Circuit Configuration
Table 1. Circuit configuration
Block
Function
HALL SENSORS
CHOPPER_SW
Two Hall elements fabricated by CMOS process.
Perform chopping in order to cancel the offset of Hall sensor.
Amplifies two Hall sensor output voltage with summation and subtraction
circuit.
Hysteresis comparator.
Generates bias current to other circuits.
Generates bias current for Hall sensors.
Generates operating clock.
Generates timing signal required for Chopper SW, AMP and COMP.
Logical circuits and CMOS output buffer.
CHOP_AMP
COMP
BIAS
HE_DRIVE
OSC
TIMING LOGIC
LATCH & LOGIC
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Pin/Function
Pin No.
1
2
3
4
Pin name
VDD
F
D
VSS
Table 2. Description of pin name and function
I/O
Function
Power supply pin
−
O
Output F (Pulse) pin
O
Output D (Direction) pin
Ground pin
−
Note
CMOS output
CMOS output
Absolute Maximum Ratings
Table 3. Absolute maximum ratings
Parameter
Symbol
Min.
Max.
Unit
+6.5
Power supply voltage
VDD
V
−0.3
+0.5
Output current
IOUT
mA
−0.5
+125
Storage temperature
TSTG
−40
°C
Note) Stress beyond these listed values may cause permanent damage to the device.
Note
F,D pin
Recommended Operating Conditions
Parameter
Power supply voltage
Operating temperature
Table 4. Recommended operating conditions
Symbol
Min.
Typ.
VDD
1.6
3.0
Ta
−30
Max.
5.5
+85
Unit
V
°C
Electrical Characteristics
Table 5. Electrical characteristics (Ta=25°C, VDD = 3.0V)
Min.
Typ.
Max.
Unit
Note
Parameter
Symbol
90
Current consumption
IDD
210
Average
µA
V
High level output Voltage
VOH
VDD-0.4
F,D pin, IOUT= −0.5mA
Low level output Voltage
VOL
0.4
V
F,D pin, IOUT= +0.5mA
Pulse drive period
TPD1
0.5
1.0
2.0
ms
24.4
Pulse drive duration time
TPD2
12.2
48.8
µs
Note) Internal data is determined just before the internal circuit turns off. And after 6.1μs (Typ.), the output
changes.
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Magnetic Characteristics
The output F and D is processed signals from internal signal A and B which is determined by the applied magnetic
field and threshold level BopV, BrpV, BopH and BrpH as follows.
Table 6. Magnetic characteristics(Ta = 25°C, VDD = 3.0V)
Parameter
Symbol
Min.
Vertical magnetic field
BopV
operating point
Vertical magnetic field
BrpV
−4.0
releasing point
Horizontal magnetic field
BopH
operating point
Horizontal magnetic field
BrpH
−4.0
releasing point
Hysteresis
BhV, BhH
(*1) Horizontal magnetic flux density is zero.
Typ.
Max.
Unit
Note
1.5
4.0
mT
(*1)
mT
(*1)
mT
(*2)
−1.5
mT
(*2)
3.0
mT
(*1), (*2)
−1.5
1.5
4.0
(*2) Vertical magnetic flux density is zero.
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Operational Characteristics
AK8776 detects the “vertical” (perpendicular to the marking side of the package) magnetic field, and the resulting
internal signal A changes state. When the magnetic field is more positive than BopV, the internal signal A changes to
‘Low’ state. And it is kept while the magnetic field remains more positive than BrpV. When the magnetic field drops
below BrpV, the internal signal A changes to ‘High’ state. Those threshold magnetic flux density levels are defined
in Table 6.
Internal signal A
S
Top(Marking)
BrpV
BhV
BopV
Bottom
0
N
N [mT]
S [mT]
Figure 2. Switching behavior of internal signal A when vertical
magnetic field is applied
AK8776 detects “horizontal “(parallel to the marking side of the package) magnetic field, and the resulting internal
signal B changes state. When the magnetic field is more positive than BopH, the internal signal B changes to ‘Low’
state. And it is kept while the magnetic field remains more positive than BrpH. When the magnetic field drops below
BrpH, the internal signal B changes to ‘High’ state. Those threshold magnetic flux density levels are defined in
Table 6.
Internal signal B
Line Marking
Top(Marking)
VSS pin
BhH
N
BopH
BrpH
S
0
N [mT]
D pin
S [mT]
Bottom
Figure 3. Switching behavior of internal signal B
when horizontal magnetic field is applied
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Behaviors of internal signal A,B and output signal F, D when a rotating magnetic field is applied on AK8776
F signal (pulse) is correspond to the result of internal signal A and B. And D signal (direction) is given by looking up
the state of signal A and B.
Direction changed
Vertical M.F.D. *
Direction changed
BopV
t
BrpV
BopH
Horizontal M.F.D.
t
BrpH
Supply voltage VDD
t
Internal signal A
(Vertical)
t
Internal signal B
(Horizontal)
t
F (Pulse)
t
D (Direction)
t
Undefined (High or Low)
F,D signal is determined.
Figure 4. Behaviors of internal signal A,B and output signal F, D
when a rotating magnetic field is applied on AK8776
*M.F.D. is Magnetic Flux Density.
Note) D signal is determined after one pulse sent out of F signal. The section which the output status is undefined
appears only in the starting up of this device.
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Functional Timing
Current consumption
TPD2 (Typ. 24.4μs)
TPD1 (Typ. 1.0ms)
IDD ON (Typ. 3.5mA)
t
Vertical M.F.D.
BopV
t
BrpV
Horizontal M.F.D.
BopH
t
BrpH
Internal signal A
(Vertical)
t
Internal signal B
(Horizontal)
t
F (Pulse)
6.1μs(Typ.)
6.1μs(Typ.)
6.1μs(Typ.)
6.1μs(Typ.)
t
Figure 5. The timing chart of current consumption and transition timing of
internal and output signal
Note)VDD=3.0V. Output signal F and D are changed at the same time.
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Typical Characteristic Data (for reference)
4
3
BopV
2
BrpV
BopH, BrpH [mT]
BopV, BrpV [mT]
4
1
0
-1
-2
-3
3
BopH
2
BrpH
1
0
-1
-2
-3
-4
-4
-30 -20 -10
0
10
20
30
40
50
60
70
80
90
-30 -20 -10
0
Ambient temperature Ta [℃]
BopV, BrpV vs. Ta (VDD=1.6V)
4
30
40
50
60
70
80
90
2
BopH
BrpH
3
BopH, BrpH [mT]
BopV, BrpV [mT]
20
4
BopV
BrpV
3
1
0
-1
-2
-3
2
1
0
-1
-2
-3
-4
-4
-30 -20 -10
0
10
20
30
40
50
60
70
80
90
-30 -20 -10
0
Ambient temperature Ta [℃]
BopV, BrpV vs. Ta (VDD=3.0V)
10
20
30
40
50
60
70
80
90
Ambient temperature Ta [℃]
BopH, BrpH vs. Ta (VDD=3.0V)
4
3
BopV
2
BrpV
BopH, BrpH [mT]
4
BopV, BrpV [mT]
10
Ambient temperature Ta [℃]
BopH, BrpH vs. Ta (VDD=1.6V)
1
0
-1
-2
-3
3
BopH
2
BrpH
1
0
-1
-2
-3
-4
-4
-30 -20 -10
0
10
20
30
40
50
60
70
80
90
-30 -20 -10
0
Ambient temperature Ta [℃]
BopV, BrpV vs. Ta (VDD=5.5V)
10
20
30
40
50
60
70
80
90
Ambient temperature Ta [℃]
BopH, BrpH vs. Ta (VDD=5.5V)
Figure 6. Temperature dependence of sensitivity
160
160
140
140
5.5V
100
80
IDD [µA]
IDD [µA]
120
3.0V
60
1.6V
120
-30℃
0℃
25℃
100
85℃
80
60
40
40
20
20
0
0
-30 -20 -10
0
10
20
30
40
50
60
70
80
90
1
2
3
4
5
6
VDD [V]
IDD vs. VDD (in various Ta)
Ambient temperature Ta [℃]
IDD vs. Ta (in various VDD)
Figure 7. Temperature dependence of current consumption
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Package
Unit in mm
4
3
1
2
センサ中心(*8)~(*11)
Sensor
Center
Marking
1:VDD
1.
VDD
2:FF
2.
3:DD
3.
4:VSS
4.
VSS
【単位 】mm
Figure 8. Package dimensions
Note 1) The center of the sensor is located within the φ0.3mm circle.
Note 2) The tolerances of dimensions with no mentions are ±0.1mm.
Note 3) Coplanarity: The differences between standoff of terminals are max. 0.1mm.
Note 4) The sensor part is located 0.4mm±0.1mm far from marking surface.
Material of terminals: Cu alloy
Material of plating for terminals: Sn 100%
Thickness of plating for terminals:10μm (Typ.)
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Marking
4
3
Marking is performed by laser
Product name :J (AK8776)
:YML
Date code
JYML
1
Y:Last one digit of manufactured year(0∼ 9)
M:Manufactured month
Jan.
C
2
Line Marking
Figure 9. Marking
Jul.
J
Feb.
D
Aug.
K
Mar.
E
Sept.
L
Apr.
F
Oct.
M
May.
G
Nov.
N
Jun.
H
Dec.
P
L:Lot(1∼ 9,A∼ Z)
Recommended External Circuit
GND
Output (D signal)
4
0.1μF
3
Top View
1
2
Output (F signal)
VDD
Figure 10. Recommended external circuit
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[AK8776]
IMPORTANT NOTICE
l These products and their specifications are subject to change without notice.
When you consider any use or application of these products, please make inquiries the sales office of
Asahi Kasei Microdevices Corporation (AKM) or authorized distributors as to current status of the
products.
l Descriptions of external circuits, application circuits, software and other related information
contained in this document are provided only to illustrate the operation and application examples of
the semiconductor products. You are fully responsible for the incorporation of these external circuits,
application circuits, software and other related information in the design of your equipments. AKM
assumes no responsibility for any losses incurred by you or third parties arising from the use of these
information herein. AKM assumes no liability for infringement of any patent, intellectual property, or
other rights in the application or use of such information contained herein.
l Any export of these products, or devices or systems containing them, may require an export license or
other official approval under the law and regulations of the country of export pertaining to customs
and tariffs, currency exchange, or strategic materials.
l AKM products are neither intended nor authorized for use as critical componentsNote1) in any safety,
life support, or other hazard related device or systemNote2), and AKM assumes no responsibility for
such use, except for the use approved with the express written consent by Representative Director of
AKM. As used here:
Note1) A critical component is one whose failure to function or perform may reasonably be
expected to result, whether directly or indirectly, in the loss of the safety or effectiveness of the
device or system containing it, and which must therefore meet very high standards of
performance and reliability.
Note2) A hazard related device or system is one designed or intended for life support or
maintenance of safety or for applications in medicine, aerospace, nuclear energy, or other fields, in
which its failure to function or perform may reasonably be expected to result in loss of life or in
significant injury or damage to person or property.
l It is the responsibility of the buyer or distributor of AKM products, who distributes, disposes of, or
otherwise places the product with a third party, to notify such third party in advance of the above
content and conditions, and the buyer or distributor agrees to assume any and all responsibility and
liability for and hold AKM harmless from any and all claims arising from the use of said product in
the absence of such notification.
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