AKM AK8777B

[AK8777B]
AK8777B
Hall Effect IC for Pulse Encoders
Overview
The AK8777B 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. The output OUTA and OUTB are switched according
to the vertical and horizontal magnetic fields applied to the device. The AK8777B is for use in the incremental pulse
encoders or rotational detection systems.
Features

4.0 to 24V supply voltage operation

Sensitivity (Vertical, Horizontal) : ±1.7mT(Typ.)

Two outputs : OUTA (detects vertical magnetic field), OUTB (detects horizontal magnetic field)

Small package: SOP-6pin

Halogen free
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Block Diagram
VDD
0.1mF
REGULATOR
VSS
BIAS
OSC
HE_DRIVE
TIMING
LOGIC
VREG
COMP
CHOP_AMP
LATCH & LOGIC
CHOPPER_SW
OUTA
OUTB
HALL SENSORS
Figure 1. Block diagram
Circuit Configuration
Table 1. Circuit configuration
Block
REGULATOR
HALL SENSORS
CHOPPER_SW
CHOP_AMP
Function
Generate internal operating voltage.
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.
COMP
Hysteresis comparator.
BIAS
Generates bias current to internal circuits.
HE_DRIVE
OSC
TIMING LOGIC
LATCH & LOGIC
Generates bias current for Hall sensors.
Generates operating clock.
Generates timing signal for internal circuits.
Logical circuits and open drain driver.
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Pin/Function
Table 2. Description of pin name and function
Pin No.
Pin name
I/O
Function
1
VDD
Power supply pin
2
TAB
(TAB pin)
3
OUTA
O
Output A pin. Relating to the vertical magnetic field.
4
OUTB
O
Output B pin. Relating to the horizontal magnetic field.
5
TAB
(TAB pin)
6
VSS
Ground pin
Note) TAB pins should be connected to VSS.
Note
Open drain
Open drain
Absolute Maximum Ratings
Parameter
Supply voltage
Output voltage
Table 3. Absolute maximum ratings
Symbol
Min.
Max.
+32
VDD
0.3
VOUT
0.3
+32
Unit
V
V
Output current
IOUT
20
mA
+150
Storage temperature
TSTG
55
C
Note) Stress beyond these listed values may cause permanent damage to the device.
Note
VSS=0V
OUTA,OUTB pin
VSS=0V
OUTA,OUTB pin
Recommended Operating Conditions
Parameter
Supply voltage
Output current
Operating temperature
Table 4. Recommended operating conditions
Symbol
Min.
Typ.
VDD
4.0
12.0
ISINK
Ta
40
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Max.
24.0
15
+125
Unit
V
mA
C
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[AK8777B]
Electrical Characteristics
Table 5. Electrical characteristics at VDD=4.0 to 24.0V, Ta= 40 to +125C
Parameter
Symbol
Min.
Typ.
Max.
Unit
Note
Current consumption
IDD
1.4
3.0
5.6
mA
OUTA,OUTB pin,
Output saturation voltage
VSAT
0.4
V
ISINK= 15mA
Output leak current
ILEAK
10
OUTA, OUTB =VDD
mA
16.7
Output refresh period
TP
12.0
30.5
ms
Magnetic Characteristics
Table 6. Magnetic characteristics at VDD=4.0 to 24.0V, Ta= 40 to +125C
Parameter
Symbol
Operating point of
BopV
vertical magnetic field
Releasing point of
BrpV
vertical magnetic field
Operating point of
BopH
horizontal magnetic field
Operating point of
BrpH
horizontal magnetic field
Hysteresis
BhV, BhH
(*1) Horizontal magnetic flux density is zero.
Min.
Typ.
Max.
Unit
Note
0.1
1.7
4.0
mT
(*1)
4.0
1.7
0.1
mT
(*1)
0.1
1.7
4.0
mT
(*2)
4.0
1.7
0.1
mT
(*2)
1.5
3.4
6.8
mT
(*1), (*2)
(*2) Vertical magnetic flux density is zero.
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Operational Characteristics
The signal OUTA switches „Low‟ state (ON) when the magnetic field perpendicular to the marking side of the
package exceeds BopV. When the magnetic field is reduces below BrpV, the OUTA goes „High‟ state (OFF).
Otherwise; that is, in case of the magnetic field strength is greater than BrpV and smaller than BopV; OUTA keeps
its status.
S
Signal OUTA
Top(Marking)
BhV
BopV
BrpV
Bottom
0
N
N
S
Figure 2. Switching behavior of the signal OUTA when vertical magnetic field is applied
The signal OUTB switches „Low‟ state (ON) when the magnetic field parallel to the marking side of the package
exceeds BopH. When the magnetic field is reduces below BrpH, the OUTB goes „High‟ state (OFF). Otherwise; that
is, in case of the magnetic field strength is greater than BrpH and smaller than BopH; OUTB keeps its status.
Signal OUTB
Line Marking
Top(Marking)
VSS pin
BhH
S
N
BopH
BrpH
0
N
OUTB pin
S
Bottom
Figure 3. Switching behavior of the signal OUTB when horizontal magnetic field is applied
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[AK8777B]
Functional Timing
TP: 16.7μs(Typ.)
Sampling
cycle
t
Vertical M.F.D.
BopV
0
BrpV
t
Horizontal M.F.D.
BopH
0
BrpH
t
signal OUTA
0
t
signal OUTB
0
t
Sampling
Cycle
Sampling
Cycle
t
t
M.F.D.
M.F.D.
BopV, BopH
0
BrpV, BrpH
BopV, BopH
0
BrpV, BrpH
t
6μs(Typ.)
signal OUTA,
signal OUTB
0
signal OUTA,
50%VDD signal OUTB
0
t
t
6μs(Typ.)
50%VDD
t
Figure 4. Timing diagram
*M.F.D. is Magnetic Flux Density.
Note) VDD=12.0V, RL=10k, CL=20pF
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Typical Characteristic Data (for reference)
Figure 5. Temperature dependence of sensitivity
Figure 6. Temperature dependence of current consumption
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[AK8777B]
Package
6
5
4
1
2
3
1:VDD
2:TAB
3:OUTA
4:OUTB
5:TAB
6:VSS
Unit in mm
Figure 7. Package dimensions
Note 1) The center of the sensitive area is located within the 0.3mm circle.
Note 2) Coplanarity: The differences between standoff of terminals are max. 0.1mm.
Note 3) The sensor part is located 0.71mm(Typ.) 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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[AK8777B]
Marking
Line Marking
6
5
4
Marking is performed by laser
5YWWL
Product name : 5 (AK8777B)
Date code
: YWWL
Y : Manufactured year
WW : Manufactured week
1
2
3
L : Lot
Figure 8. Marking
Recommended External Circuit
10kΩ
VDD
Output (OUTA)
GND
5
4
Top View
1
2
3
VDD
10kΩ
VDD
0.1μF
6
Output (OUTB)
Figure 9. Recommended external circuit
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IMPORTANT NOTICE
 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.
 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
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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
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