[AK8779A]
AK8779A
Hall Effect IC for Pulse Encoders
1.
General Description
The AK8779A is a Hall effect latch which detects both “vertical magnetic field” and “horizontal magnetic
field” (perpendicular and parallel to the marked side of the package) at the same time. The pulse output
F and the direction output D are switched according to the vertical and horizontal magnetic fields applied
to the device. The direction is calculated internally and output D is switched on a rising or falling edge of
output F. The AK8779A is for use in the incremental pulse encoders or rotational detection systems.
2. Features
Supply Voltage:
Operation Temperature:
Sensitivity (Vertical):
Sensitivity (Horizontal):
Two Outputs:
Package:
3.8 to 24V
40 to 150ºC
±2.0mT(Typ.), ±4.0mT(Max.)
±2.0mT(Typ.), ±4.0mT(Max.)
F (Pulse)
D (Direction)
6-pin SOP (RoHS Compliant, Halogen free)
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3.
Table of Contents
1.
2.
3.
4.
General Description ............................................................................................................................ 1
Features .............................................................................................................................................. 1
Table of Contents ................................................................................................................................ 2
Block Diagram and Functions ............................................................................................................. 3
4.1. Block Diagram.............................................................................................................................. 3
4.2. Functions ..................................................................................................................................... 3
5. Pin Configurations and Functions ....................................................................................................... 4
5.1. Pin Configurations ....................................................................................................................... 4
5.2. Functions ..................................................................................................................................... 4
6. Absolute Maximum Ratings ................................................................................................................ 4
7. Recommended Operating Conditions................................................................................................. 5
8. Electrical Characteristics ..................................................................................................................... 5
9. Magnetic Characteristics..................................................................................................................... 5
10.
Magnetic Field Detection ................................................................................................................. 6
10.1.
Definition of Vertical Magnetic Field’s Polarity ......................................................................... 6
10.2.
Definition of Horizontal Magnetic Field’s Polarity .................................................................... 6
10.3.
Behaviors of Internal and Output Signals when a Rotating Magnetic Field Is Applied on The
AK8779A ................................................................................................................................................. 7
11.
Operational Timing .......................................................................................................................... 8
12.
Recommended External Circuit ...................................................................................................... 9
13.
Typical Characteristics Data (for reference).................................................................................. 10
14.
Package ..........................................................................................................................................11
14.1.
Outline Dimensions .................................................................................................................11
14.2.
Material of Terminals ...............................................................................................................11
14.3.
Land Pattern ........................................................................................................................... 12
14.4.
Marking................................................................................................................................... 12
IMPORTANT NOTICE .......................................................................................................................... 13
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4.
Block Diagram and Functions
4.1. Block Diagram
VDD
0.1mF
REGULATOR
VSS
BIAS
OSC
HE_DRIVE
TIMING
LOGIC
VREG
CHOP_AMP
COMP
LATCH & LOGIC
CHOPPER_SW
F
D
HALL SENSORS
Figure 1. AK8779A Block Diagram
4.2. Functions
Table 1. Circuit configuration
Block Name
Function
REGULATOR
Generate internal operating voltage.
HALL SENSORS
Two Hall elements fabricated by CMOS process.
Hall sensor drive switch.
CHOPPER_SW
Perform chopping in order to cancel the offset of Hall sensor.
Amplify two Hall sensor output voltages with summation and subtraction
CHOP_AMP
circuit.
COMP
Hysteresis comparator.
BIAS
Generate bias current to internal circuits.
HE_DRIVE
Generate bias current for Hall sensors.
OSC
Generate operational clock.
TIMING LOGIC
Generate timing signal for internal circuits.
LATCH & LOGIC
Logical circuits and open drain driver.
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5. Pin Configurations and Functions
5.1. Pin Configurations
Line Marking
6
5
4
1
2
3
Figure 2. Pin Layout
5.2. Functions
Table 2. Description of pin name and function
Pin No. Pin Name
I/O
Function
1
F
O
Output pin (relating to the pulse output)
2
TAB
(TAB pin)
3
D
O
Output pin (relating to the direction output)
4
VDD
Power supply pin
5
TAB
(TAB pin)
6
VSS
Ground pin
Description
Open Drain
(* 1)
Open Drain
(* 1)
* 1. The TAB pin should be connected to the VSS pin.
6.
Table 3. Absolute maximum ratings
Parameter
Symbol
Supply Voltage
VDD
Absolute Maximum Ratings
Min.
0.3
Max.
32
Unit
V
Output Voltage
VOUT
0.3
32
V
Output Current
Storage Temperature
ISINK
TSTG
55
20
150
mA
ºC
Description
VSS = 0V
F pin, D pin
VSS = 0V
F pin, D pin
Operation at or beyond these limits may result in permanent damage to the device. Normal operation is
not guaranteed at these extremes.
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7. Recommended Operating Conditions
Table 4. Recommended operating conditions
Parameter
Symbol
Supply Voltage
VDD
Output Current
ISINK
Operation Temperature
Ta
8.
Min.
3.8
Typ.
12
40
Max.
24
15
150
Unit
V
mA
ºC
Electrical Characteristics
Table 5. Electrical characteristics at VDD = 3.8 to 24V, Ta = 40 to 150ºC
Symbol
Parameter
Min. Typ.
Max.
Unit Description
Current Consumption
IDD
1.7
3.5
6.2
mA VDD = 3.8 to 24V
Current Consumption (2)
IDD2
1.7
3.5
6.0
mA VDD = 3.8 to 18V
Output Saturation Voltage
VSAT
0.4
V
F pin, D pin, ISINK = 15mA
Output Leak Current
ILEAK
10
µA
F, D = VDD
Output Refresh Period
Tp
5.0
8.3
16.7
µs
9.
Magnetic Characteristics
Table 6. Magnetic characteristics at VDD = 3.8 to 24V, Ta = 40 to 150ºC
Parameter
Symbol
Min.
Typ.
Operate point of vertical magnetic field
BopV
0.5
2.0
Release point of vertical magnetic field
BrpV
4.0
2.0
Operate point of horizontal magnetic field
BopH
0.5
2.0
Release point of horizontal magnetic field
BrpH
4.0
2.0
Hysteresis
BhV, BhH
2.0
4.0
Magnetic offset
BoffV, BoffH
0.0
1.1
Max.
4.0
0.5
4.0
0.5
6.4
+1.1
Unit
mT
mT
mT
mT
mT
mT
Description
(* 2)
(* 2)
(* 3)
(* 3)
(* 2, * 3, * 4)
(* 2, * 3, * 5)
* 2. Horizontal magnetic flux density is zero.
* 3. Vertical magnetic flux density is zero
* 4. Bh = Bop – Brp
* 5. Boff = (Bop + Brp) / 2
Internal signal A/B
Bh/2
Bh/2
N
B
0
Brp
S
Boff
Bop
Figure 3. Definition of Bh and Boff
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10. Magnetic Field Detection
10.1. Definition of Vertical Magnetic Field’s Polarity
The internal signal A switches ‘L’ (ON) when the magnetic field perpendicular to the marking side of the
package exceeds BopV. When the magnetic field is reduced below BrpV, the internal signal A goes ‘H’
(OFF). Otherwise; that is, in case of the magnetic field strength is greater than BrpV and smaller than
BopV; the internal signal A keeps its status.
Internal signal A
Line Marking
BhV
N
BrpV
0
BopV
B
S
Figure 4. Switching behavior of the internal signal A when vertical magnetic field is applied
10.2. Definition of Horizontal Magnetic Field’s Polarity
The internal signal B switches ‘L’ (ON) when the magnetic field parallel to the marking side of the
package exceeds BopH. When the magnetic field is reduced below BrpH, the internal signal B goes ‘H’
(OFF). Otherwise; that is, in case of the magnetic field strength is greater than BrpH and smaller than
BopH; the internal signal B keeps its status.
Internal signal B
Line Marking
BhH
N
BrpH
0
B
BopH
S
Figure 5. Switching behavior of the internal signal B when horizontal magnetic field is applied
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10.3. Behaviors of Internal and Output Signals when a Rotating Magnetic Field Is Applied on
The AK8779A
The F signal (pulse) is correspond to the result of EX-OR operation of internal signal A and B. The D
signal (direction) is calculated by status of internal signal A and B.
Direction changed
Vertical M. F. D.
BopV
0
t
BrpH 0
t
BrpV
Horizonatal M. F. D.
Direction changed
BopH
Supply voltage VDD
0
t
0
t
0
t
0
t
Internal signal A
(Vertical)
Internal signal B
(Horizontal)
F (Pulse)
D (Direction)
0
t
Undefined ("H" or "L")
F, D signal is determined.
Figure 6. Behaviors of Internal Signal A, B and Output Signal F, D with Rotating Magnetic Field
* M.F.D. = Magnetic Flux Density
* D signal is determined after one F signal pulse is sent out. The indeterminate output state appears
only in the powering up of this device.
* F and D signals are changed at the same time.
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11. Operational Timing
Tp: 8.3μs (Typ.)
Sampling Cycle
t
Vertical M.F.D.
BopV
0
BrpV
t
Horizontal M.F.D.
BopH
0
t
BrpH
Internal signal A
(Vertical)
0
t
0
t
Internal signal B
(Horizontal)
F (Pulse)
0
t
Figure 7. Output Signal Timing Diagram
Direction changed
Direction changed
Sampling Cycle
t
Vertical M.F.D.
M.F.D.
Horizontal M.F.D.
BopV,BopH
0
t
BrpV,BrpH
4μs(Typ.)
4μs(Typ.)
4μs(Typ.)
F (Pulse)
4μs(Typ.)
50%VDD
4μs(Typ.)
D (Direction)
t
4μs(Typ.)
50%VDD
Figure 8. Output Signal Timing Diagram (in detail)
* M.F.D. = Magnetic Flux Density
* VDD = 12V, RL = 10k, CL = 20pF
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12. Recommended External Circuit
0.1μF
VSS
4
VDD
Top View
F
1
10kΩ
GND
5
10kΩ
6
VDD
D
2
3
Output (D)
Output (F)
Figure 9. Recommended External Circuit
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13. Typical Characteristics Data (for reference)
4
4
BopV
BrpV
3
2
BopH, BrpH [mT]
BopV, BrpV [mT]
2
1
0
-1
-2
-3
-4
-25
0
25
50
75
100
0
-1
-2
-3
125
150
-50
-25
0
25
50
75
100
Ambient temperature Ta [℃]
Ambient temperature Ta [℃]
BopV, BrpV vs. Ta (VDD= 3.8V)
BopH, BrpH vs. Ta (VDD= 3.8V)
4
125
4
BopV
BrpV
3
150
BopH
BrpH
3
2
2
BopH, BrpH [mT]
BopV, BrpV [mT]
1
-4
-50
1
0
-1
-2
-3
-4
1
0
-1
-2
-3
-4
-50
-25
0
25
50
75
100
125
150
-50
-25
0
25
50
75
100
Ambient temperature Ta [℃]
Ambient temperature Ta [℃]
BopV, BrpV vs. Ta (VDD= 12V)
BopH, BrpH vs. Ta (VDD= 12V)
4
125
4
BopV
BrpV
3
150
BopH
BrpH
3
2
BopH, BrpH [mT]
2
BopV, BrpV [mT]
BopH
BrpH
3
1
0
-1
-2
-3
1
0
-1
-2
-3
-4
-4
-50
-25
0
25
50
75
100
125
-50
150
-25
0
25
50
75
100
Ambient temperature Ta [℃]
Ambient temperature Ta [℃]
BopV, BrpV vs. Ta (VDD= 24V)
BopH, BrpH vs. Ta (VDD= 24V)
125
150
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
3.8V
12V
24V
IDD [mA]
IDD [mA]
Figure 10. Temperature Dependence of Bop, Brp
-50
-25
0
25
50
75
100
125
150
Ambient temperature Ta [℃]
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
40℃
25℃
50℃
150℃
0
2
4
6
8
10
12
14
16
18
20
22
24
26
VDD [V]
IDD vs. Ta (in various VDD)
IDD vs. VDD (in various Ta)
Figure 11. Temperature Dependence of Current Consumption
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14. Package
14.1. Outline Dimensions
6-pin SOP (Unit: mm)
Figure 12. Outline Dimensions
* The center of the sensitive area is located within a φ0.3mm circle.
* Lead flatness: The standoff differences among terminals are Max. 0.1mm.
* The sensor part is located at 0.71mm (Typ.) deep from the marked surface.
14.2. Material of Terminals
Material:
Plating:
Thickness:
Cu alloy
Sn 100%
10µm (Typ.)
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14.3. Land Pattern
Unit: mm
Figure 13. Land Pattern
14.4. Marking
Line Marking
6
5
4
Marking is performed by laser
Product name
Date code
AYWWL
1
2
A(AK8779A)
YWWL
Y: Manufactured Year
WW: Manufactured Week
L: Lot Number
3
Figure 14. Marking
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IMPORTANT NOTICE
0. Asahi Kasei Microdevices Corporation (“AKM”) reserves the right to make changes to the
information contained in this document without notice. When you consider any use or
application of AKM product stipulated in this document (“Product”), please make inquiries the
sales office of AKM or authorized distributors as to current status of the Products.
1. All information included in this document are provided only to illustrate the operation and
application examples of AKM Products. AKM neither makes warranties or representations with
respect to the accuracy or completeness of the information contained in this document nor
grants any license to any intellectual property rights or any other rights of AKM or any third party
with respect to the information in this document. You are fully responsible for use of such
information contained in this document in your product design or applications. AKM ASSUMES
NO LIABILITY FOR ANY LOSSES INCURRED BY YOU OR THIRD PARTIES ARISING FROM
THE USE OF SUCH INFORMATION IN YOUR PRODUCT DESIGN OR APPLICATIONS.
2. The Product is neither intended nor warranted for use in equipment or systems that require
extraordinarily high levels of quality and/or reliability and/or a malfunction or failure of which
may cause loss of human life, bodily injury, serious property damage or serious public impact,
including but not limited to, equipment used in nuclear facilities, equipment used in the
aerospace industry, medical equipment, equipment used for automobiles, trains, ships and
other transportation, traffic signaling equipment, equipment used to control combustions or
explosions, safety devices, elevators and escalators, devices related to electric power, and
equipment used in finance-related fields. Do not use Product for the above use unless
specifically agreed by AKM in writing.
3. Though AKM works continually to improve the Product’s quality and reliability, you are
responsible for complying with safety standards and for providing adequate designs and
safeguards for your hardware, software and systems which minimize risk and avoid situations
in which a malfunction or failure of the Product could cause loss of human life, bodily injury or
damage to property, including data loss or corruption.
4. Do not use or otherwise make available the Product or related technology or any information
contained in this document for any military purposes, including without limitation, for the design,
development, use, stockpiling or manufacturing of nuclear, chemical, or biological weapons or
missile technology products (mass destruction weapons). When exporting the Products or
related technology or any information contained in this document, you should comply with the
applicable export control laws and regulations and follow the procedures required by such laws
and regulations. The Products and related technology may not be used for or incorporated into
any products or systems whose manufacture, use, or sale is prohibited under any applicable
domestic or foreign laws or regulations.
5. Please contact AKM sales representative for details as to environmental matters such as the
RoHS compatibility of the Product. Please use the Product in compliance with all applicable
laws and regulations that regulate the inclusion or use of controlled substances, including
without limitation, the EU RoHS Directive. AKM assumes no liability for damages or losses
occurring as a result of noncompliance with applicable laws and regulations.
6. Resale of the Product with provisions different from the statement and/or technical features set
forth in this document shall immediately void any warranty granted by AKM for the Product and
shall not create or extend in any manner whatsoever, any liability of AKM.
7. This document may not be reproduced or duplicated, in any form, in whole or in part, without
prior written consent of AKM.
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