[AK7451]
AK7451
Zero Latency Angle Sensor IC
1. General Description
The AK7451 is a magnetic rotational angle sensor IC of Si monolithic with a built-in Hall element, and
easily achieve a non-contact rotation angle sensor in combination with diametrically magnetized two
pole magnet.
By detecting the magnetic field parallel vector to the IC package surface, the AK7451 outputs the
absolute angular position of the magnet, and the relative angular position.
By transverse magnetic field detection method using a magnetic flux concentrator, the AK7451 has
excellent axial misalignment immunity.
AK7451 is the Zero Latency rotation angle sensor to follow up to 20,000rpm with the architecture of the
tracking servo system, it is suitable to various motor drive applications and an encoder applications.
2. Features
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Monolithic integrated 360 degrees angle sensor IC containing Hall element.
Easy to make a contactless rotation sensor with diametrically magnetized two pole magnet.
Interfaces : SPI(absolute angle), ABZ phase output (incremental Interface), UVW phase output
12bit angle resolution
Less than ±0.6 deg. angle accuracy at 25 ºC
Maximum tracking speed : 333 rps (20,000 rpm)
Angle output delay time: 1.8µs
Operating ambient temperature: -40 to 125ºC
Various abnormal detection; abnormal magnetic flux density range etc.
Various setting functions; angle zero point, rotation direction, ABZ resolution/hysteresis etc.
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3. Table of Contents
1. General Description ............................................................................................................................ 1
2. Features .............................................................................................................................................. 1
3. Table of Contents ................................................................................................................................ 2
4. Block Diagram and Functions ............................................................................................................. 3
5. Pin Configurations and Functions ....................................................................................................... 5
6. Absolute Maximum Ratings ................................................................................................................ 6
7. Recommended Operating Conditions................................................................................................. 6
8. EEPROM Characteristics.................................................................................................................... 6
9. Electrical and Magnetic Characteristics .............................................................................................. 7
10. Serial Interface Characteristics ........................................................................................................... 8
11. Digital Output Characteristics ........................................................................................................... 10
12. Instructions .........................................................................................................................................11
13. Mode Transition Diagram and Conditions ........................................................................................ 12
14. Serial Interface .................................................................................................................................. 13
15. Register / EEPROM Address Map / Configration .......................................................................... 15
16. ABZ Output Figure ............................................................................................................................ 26
17. UVW Output Figure ........................................................................................................................... 27
18. Abnormal Detection Functions .......................................................................................................... 28
19. Angle Zero Position at Shipment, and Relation between Magnet Angle Position and Output ...... 29
20. Package Information ......................................................................................................................... 30
20.1. Outline Dimensions ..................................................................................................................... 30
20.2.
Marking................................................................................................................................... 31
Important Notice ....................................................................................................................................... 32
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4. Block Diagram and Functions
VDD
ATPGE
ESD
HE_X
HE_X
REGULATE
_ANA
POR
ARVDD
DRVDD
DMODE
V
V
TESTA
Vx
X_
HE_Y
Y_
Type2
PRA_
PRA_Y
Detector
Tracking
SWAP
SWAP
CHOP
HE-Drive
Fault
ADC _X
PRA_X
CHOP
PRA_
HE_Y
REGULATE
_DIG
ADC_Y
Vｙ
Loop
ENCODER
LOGIC
OSC
D6
ERROR
U
V
W
A
B
Z
V&I
Reference
EEPROM
Serial IF
(SPI)
CS
SCLK
MOSI
MISO
VSS
Figure 1. Functional block diagram of AK7451
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Table 1. Description of circuit block
Circuit Block
Function
Si monolithic Hall elements. These detect X/Y-compositions of
HE-X/Y
flux which are parallel to the IC package surface by using the
magnetic concentrator and converts to an electrical signal.
Switch its direction of drive current in order to lower offset and
X_CHOP, Y_CHOP
noise for the Hall elements.
HE Drive
Drive Hall elements by constant current.
PRA_X,PRA_Y
Amplify signals from Hall elements.
Reduce mismatch of each amplifier gain and Hall element
PRA_SWAP
current.
AD converter for converting the Hall electromotive force signal
ADC_X，ADC_Y
amplified in the preamplifier into a digital signal.
OSC_8MEG
Generate a master clock (8 MHz).
V & I Reference
Generate reference voltage / current.
Closed loop circuit to calculate an angle from the digitalized Hall
Type2 Tracking Loop
signal.
POR
Power-On-Reset circuit.
Regulate the power supply voltage and generate the internal
REGULATE_ANA
ARVDD which is for analog circuit.
Regulate the power supply voltage and generate the internal
REGULATE_DIG
DRVDD which is for digital circuit.
EEPROM
Non-volatile memory.
Detect abnormal status such as magnetic flux density range and
Fault Detector
losing tracking state.
Generate ABZ and UVW phase signal based on absolute angle
Encoder Logic
data.
Serial IF
4-wire SPI interface circuit.
ESD
Protection circuit for ESD
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5. Pin Configurations and Functions
Figure 2. Pin assignment of AK7451
Table 2. Pin configuration and functions of AK7451
No.
Pin Name I/O
Type
Description
1
A
O
Digital
A-phase Pulse Signal
2
B
O
Digital
B-phase Pulse Signal
3
Z
O
Digital
Z-phase Pulse Signal
4
U
O
Digital
U-phase Pulse Signal
5
V
O
Digital
V-phase Pulse Signal
6
W
O
Digital
W-phase Pulse Signal
7
ERROR
O
Digital
ERROR output PIN
8
VDD
Power
Power Supply PIN
9
VSS
GND
Ground PIN
10
TESTA
I/O
Analog
TEST dedicated PIN. This pin should be non-connection.
11
DMODE
I
Digital
TEST dedicated PIN. This pin should be non-connection.
12
ATPGE
I
Digital
TEST dedicated PIN. This pin should be non-connection.
13
MISO
O
Digital
SPI output data signal
14
MOSI
I
Digital
SPI Input Data Signal
15
SCLK
I
Digital
SPI Clock Signal
16
CS
I
Digital
SPI Chip Select Signal
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6. Absolute Maximum Ratings
Table 3. Absolute Maximum Ratings
Parameter
Symbol
Power Supply Voltage
VDDA
Voltage on Output pin
Output Current on
Output pin 1
Output Current on
Output pin 2
Input pin Voltage
Min.
-0.3
Max.
6.5
Units
V
VOUT
-0.3
VDDA
V
IOUT1
-1.25
1.25
mA
IOUT2
-10
10
mA
VIN
-0.3
VDDA + 0.3
(≦6.5V)
V
Notes
VDD pin
MISO,ERROR,A,B,Z,
U,V,W pin
MISO pin
ERROR,A,B,Z,U,V,W
pin
MOSI,CS,SCLK,
DMODE,ATPGE,
TESTA pin
Storage temperature
TSTG
-50
+150
ºC
WARNING: Stress beyond these listed values may cause permanent damage to the device. Even it may
not cause damage on the device; it may affect its reliability and longevity.
Normal operation is not guaranteed. Each voltage is with respect to VSS pin.
7. Recommended Operating Conditions
Table 4. Operating conditions
Parameter
Symbol
Min.
Typ.
Max.
Units
Notes
Power Supply Voltage
under Operating
VDD
4.5
5
5.5
V
VDD pin
Conditions
Operating Ambient
Ta
-40
+125
ºC
Temperature
WARNING: Exceeding the operation conditions, the electric and magnetic characteristics are not
guaranteed. Voltage is with respect to VSS pin.
8. EEPROM Characteristics
Table 5. EEPROM Characteristics
Conditions : VDD =4.5 to 5.5V
Parameter
Symbol
Endurance to
Wf
rewriting
Ambient Temperature
TMEM
in writing
Writing time
Wt
Min.
Typ.
0
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Max.
Units
1000
cycle
85
ºC
5
ms
Notes
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9. Electrical and Magnetic Characteristics
Table 6 . Electrical and Magnetic Characteristics
Conditions（unless otherwise specified）: Ta=-40 to 125ºC, VDD=4.5 to 5.5V
Parameter
Symbol
Conditions
Min.
Typ.
Magnetic Flux
BRANGE
30
50
Density Range
Angle Detection
ARANGE
0
Range
Angle Resolution
ARES
12bit
0.088
Angle Linearity Error
AINL
-0.6
at 25ºC
(Note 1)
Operating temperature range
Thermal Angle Drift
ADRIFT
-0.9
(with reference to 25ºC)
Angle hysteresis
AHYS
at 25ºC
Width
Output noise
HNOISE
at 50mT
-2
Angle Tracking
FSAMP
Ability
Angle Output Delay
at ABZ hysteresis configuration
TD
Time (Note 2)
=”Invalid”
Power On Time
TSTO
25
(Note 3)
Supply current
ISUP
No Output Load
12.7
Max.
Unit
70
mT
3
deg.
deg.
+0.6
deg.
+0.9
deg.
0.3
deg.
2
LSB
20000
rpm
1.8
µs
30
ms
15.7
mA
Note 1. If ABZ resolution configuration is set to other than exponentiation of 2, the father angle linearity
error is added to the specified value in 0 to 1LSB (0 to 0.088degree).
Note 2. This value is in case that ABZ hysteresis configuration is set to “Invalid”. This value is dependent
on ABZ hysteresis configuration. Whenever the setting value is increased, the angle output delay time
value increases by 0.5µs at a time.
Note 3. It is the time from Power-On to becoming high on ERROR pin through judging magnetic flux
range error and tracking error. This time is including the circuit setup time, the tracking angle time, the
self-diagnosis of error time. This parameter is not tested at mass production.
4.5V
VDD
Power on time TSTO
ERROR PIN
Time
Figure 3. Waveform of VDD and ERROR pin at start-up
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10. Serial Interface Characteristics
Table 7. Serial I/F DC Characteristics
Conditions : Ta=-40 to 125ºC, VDD=4.5 to 5.5V
Parameter
Symbol
PIN
Conditions
Input High
CS,SCLK,
VHSI
Level
MOSI
Input Low
CS,SCLK,
VLSI
Level
MOSI
CS,SCLK,
Input Current
ISI
MOSI
Output Current
ISO
MISO
Output High
VHSO
MISO
ISO=1mA (source)
Level
Output Low
VLSO
MISO
ISO=1mA (sink)
Level
Output Load
CSO
MISO
Capacity
Table 8. Serial I/F AC Characteristics
Conditions : Ta=-40 to 125ºC, VDD=4.5 to 5.5V
Parameter
Symbol
Time from fall of CS to start of
t1
CLK
Necessary Time from end of
t2
SCLK to rise of CS
Set-up time of input data
t3
Hold time of input data
t4
Time to fix output data
t5
Time from rise of CS to Hi-Z of
t6
MISO
Transition time from 0.2VDD to
t7
0.8VDD of output data
Transition time from 0.8VDD to
t8
0.2VDD of output data
SCLK High time
t9
SCLK Low time
t10
SCLK Rise time (Note 4)
t11
SCLK Fall time (Note 4)
t12
Idle time in writing register
t13
Idle time in writing EEPROM
t13
SCLK Frequency
-
Min
Typ.
Min.
Typ.
Max.
0.7VDD
V
0.3VDD
V
-10
+10
µA
-1
1
mA
0.8VDD
V
-0.3
Max
Unit
100
ns
100
ns
70
70
150
ns
ns
ns
500
ns
100
ns
100
ns
0
200
200
30
30
2.5
5
0.001
Unit
2000
0.2VDD
V
100
pF
Notes
ns
ns
ns
ns
µs
ms
kHz
Note 4. These parameters are not tested at mass production.
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Figure 4. AC Timing of Serial I/F
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11. Digital Output Characteristics
Table 9. Digital Output DC Characteristics
Conditions :Ta=-40 to 125ºC, VDD=4.5 to 5.5V
Parameter
Symbol
Pin
Notes
A,B,Z,
Output Current
IDO
U,V,W,
ERROR
A,B,Z,
Output Low
VLDO
U,V,W,
IDO=2mA(sink)
Level
ERROR
A,B,Z,
Output High
VHDO
U,V,W,
IDO=2mA(source)
Level
ERROR
A,B,Z,
Output Load
CDO
U,V,W,
Capacity
ERROR
Table 10. Digital Output AC Characteristics
Conditions :Ta=-40 to 125ºC, VDD=4.5 to 5.5V
Parameter
Symbol
Pin
Rise time
TRDO
A,B,Z,
U,V,W,
ERROR
Fall time
TFDO
A,B,Z,
U,V,W,
ERROR
Notes
CDO=100pF,
IDO=2mA(source)
Time from 0.2VDD to
0.8VDD
CDO=100pF,
IDO=2mA(sink)
Time from 0.8VDD to
0.2VDD
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Min
Typ.
Max
Unit
-2
2
mA
-0.3
0.2VDD
V
0.8VDD
Min
V
Typ.
100
pF
Max
Unit
150
ns
150
ns
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12. Instructions
The AK7451’s function is described in this section. The function is roughly divided into programing
procedure (for various setup) and an angle measurement procedure. The operation procedure is as
follows.
1. The AK7451 will start as “Normal Mode” after power on automatically.
2. Transfer to “User Mode” and write configuration parameters in EEPROM and then verify the data.
3. Transfer to “Normal Mode” and then The AK7451 will output the angle data based on programed
parameter.
1. Transfer to “Normal Mode”.
2. Input the “read angle command” as OPCODE”1001” via SPI, when the absolute angle data is
needed. If relative angle data is needed, count the ABZ output pulses. The ABZ pulses and UVW
pulses are outputted right after startup along with magnet rotating.
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13. Mode Transition Diagram and Conditions
This IC has the following two modes and starts with “Normal Mode” at start up.
In the “Normal Mode”, this sensor will be operated as angle output mode. User can read the angle data
via SPI pin and ABZ pin and also can transfer to “User Mode” by using specific OPCODE. And also in
this mode, UVW output is available to detect the magnet rotor position in BCDL motor driving.
In the “User Mode”, the user can set the various operation conditions via SPI communication. The
settable item will be described later in this section.
Mode name
Normal Mode
Note
In this mode, The absolute angle data including error bit, parity bit and mode
information will be outputted via SPI communication by inputting specific OPCODE.
And the ABZ and UVW pulses are outputted automatically along with magnet
rotating.
User Mode
Do not use the angle data (ABZ and UVW pulses) in this mode.
The following functions are available in this mode.
a. Magnetic flux density measurement
b. Abnormal state checking
c. Memory lock
d. Angle zero position setting
e. ABZ output enable/disable and resolution, hysteresis setting
f. Abnormal detection enable/disable setting
g. Rotation direction setting
h. UVW output enable/disable and the number of output pulses, hysteresis setting
Note 5. In user mode, output on ERROR PIN is low state (abnormal status). And the accuracy of
magnetic flux density measurement is not guaranteed.
Each mode can be changed by writing specific OPCODE and specific data on specific address as the
diagram below.
Normal Mode
Addr.0x02
OPCODE：0101
DATA：0
or
Re Power-On
Addr.0x02
OPCODE：
0101
DATA：0x50F
User Mode
Figure 5. Mode transition diagram
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14. Serial Interface
When register/memory setting or absolute angle measurement is needed, use SPI communication.
The serial communication protocol and each register/memory description are described in this section.
● Data format
1) Write memory/register in User Mode
1
2
3
4
5
6
7
8
9
10
11
13
12
14
15
16
17
18
19
21
20
22
23
24
CS
SCL
MOSI
*
MISO
Hi-Z
O3 O2 O1 O0 A6 A5 A4 A3 A2 A1 A0
2) Read memory
1
2 register
3
4
5 in6 User
7
8 Mode
9
10
11
* D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
13
12
14
15
16
17
18
19
20
21
22
23
*
24
CS
SCL
MOSI
MISO
*
*
O3 O2 O1 O0 A6 A5 A4 A3 A2 A1 A0
Hi-Z
D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Hi-Z
3) Read angle data in Normal Mode
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
CS
SCL
MOSI
*
MISO
Hi-Z
*
O3 O2 O1 O0
MD P1 P2
E D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Hi-Z
Figure 6. Timing Chart of Serial I/F
Note 6. Figure symbols are as following;
‘Ox’:
Operation Code
‘Ax’:
Memory/Register Address
‘MD’:
Mode Information （MD is “0” in Normal Mode, And “1” in User Mode
‘Dx’:
Data
‘P1’:
Parity Bit for Angle Data[11:6]
‘P2’:
Parity Bit for Angle Data[5:0]
‘E’ :
Error Bit (Normal=1,Abnormal=0)
‘*’ :
Don’t Care.
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Note 7. Parity bit is odd parity in normal and even parity in abnormal. And the ABZ hysteresis
configuration which is described later in this section is reflected in read angle data.
Note 8. Send data and receive data are from MSB to LSB in sequence.
Table 11. OPCODE Specification
OPCODE name
OPCODE[3：0]
0000
N.A.
0001
Write EEPROM
0010
Read EEPROM
0011
Write Register
0100
Read Register
0101
Change MODE
0110
0111
N.A.
N.A.
1000
Angle Data Renew
1001
1010
1011
1100
1101
1110
1111
Read Angle
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
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Note
Able to write a data on EEPROM.
Able to read an EEPROM.
Able to write a data on register.
Able to read a register.
Able to change between normal mode
and user mode. Transition conditions
are described in ‘14.1. Mode Transition
Diagram and Conditions ‘.
Update the ANG, MAG, ERRMON, ERR
bit data.
Read the angle data.
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15. Register / EEPROM Address Map / Configration
● Register Address Map
Table 12. Register Address Map
Addr.
[HEX]
Register
symbol
R/W Permission
Normal
Mode
User
Mode
0x00
0x01
0x02
0x03
R_ANG
R_MAG
R_CHMD
R_ERRMON
R
N.A.
W
N.A.
R
R
R/W
R
0x04
0x05
0x06
0x07
R_ZP
R_RDABZ
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
R/W
R/W
0x08
0x09
0x0A
R_MLK
R_EBDIS
R_UVW
N.A.
N.A.
N.A.
R
R/W
R/W
Note
12bit angle data
Magnetic flux density strength（roughly 1LSB/mT）
For mode state
Error monitor
(This register will show what kind of error is.)
For set up angle zero point
For set up “Rotation direction”, “Z phase output
form”, “ABZ output enable/disable”, “ABZ
Hysteresis” and “ABZ resolution”.
For memory lock
For set up abnormal detection disable
For set up “UVW output enable/disable”, “UVW
Hysteresis” and “UVW resolution”.
Note 9. N.A. = Not Available, R = Read Only, R/W = Read and Write
Note 10. Address 0x02 is only able to be changed by writing OPCODE”0101”
● Each Register Configurations
R_ANG Register (Register Address:0x00)
R_ANG
Content
D11
D10
D9
D8
D7
D6
D5
R_ANG[11:0]
D4
D3
D2
D1
D0
Register Function: This register contains an output angle data. The angle data consists with the
following angle position. And the ABZ hysteresis configuration which is described later in this
section is reflected in this register’s value.
Angle Position [°]
0
（360÷4096）×1
（360÷4096）×2
（360÷4096）×3
：
（360÷4096）×4095
R_ANG[11:0]
0x000
0x001
0x002
0x003
：
0xFFF
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R_MAG Register (Register Address:0x01)
R_MAG
Content
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
R_MAG[6:0]
D1
D0
Register Function: This register contains a magnetic flux density strength data. The magnetic flux
density strength data consists with the following magnetic flux density strength.
Magnetic Flux Density
Strength [mT]
0
1
2
3
：
127
R_MAG[6:0]
0x00
0x01
0x02
0x03
0x7F
Note 11. This magnetic flux density measurement data’s accuracy which is stored in this register is not
guaranteed, It is recommended to use for only reference.
R_CHMD Register (Register Address：0x02)
R_CHMD
Content
D11
D10
D9
D8
D7
D6
D5
D4
R_CHMD[11:0]
D3
D2
D1
D0
Register Function: This register is to configure the mode (Normal Mode/User Mode). This register
can be written by using OPCODE [0101]. Each mode configuration is the following.
Mode
R_CHMD[11:0]
Default
Normal Mode
0x000
●
User Mode
0x50F
R_ERRMON Register (Register Address：0x03)
R_ERRMON
D11
D10
D9
D8
D7
Content
D6
D5
D4
D3
D2
D1
D0
R_ERRMON
[1:0]
Register Function : This register shows the error state. Corresponding bit data is 0 in the abnormal
state. Relation between the abnormal state and bit data is the following.
Abnormal State
Bit data
Value in
Value in
Abnormal State
Normal State
Magnetic Flux Density
R_ERRMON[1]
0
1
Strength Abnormity
Tracking Lost
R_ERRMON[0]
0
1
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R_ZP Register (Register Address：0x06)
R_ZP
Content
D11
D10
D9
D8
D7
D6
D5
R_ZP[11:0]
D4
D3
D2
D1
D0
Register Function: This register is available for setting arbitrarily angle position as zero position.
Relation between the angle position and the ZP data is the following. The register value is duplicated
from corresponding memory after power on or, when the mode transferred to "Normal Mode" from
“User Mode”.
Zero Point Angle Position
[°]
0
（360÷4096）×1
（360÷4096）×2
（360÷4096）×3
：
（360÷4096）×4095
R_ZP[11:0]
Default
0x000
0x001
0x002
0x003
：
0xFFF
●
Note 12. A setup of this register is reflected in ABZ and UVW output.
R_RDABZ Register (Register Address：0x07)
R_RDABZ D11
Content
D10
D9
D8
D7
D6
D5
D4
R_RD R_Z_MODE R_ABZ_E R_ABZ_HYS[2:0]
D3 D2
D1
D0
R_ABZ_RES[3:0]
Register Function: This register is used for configuring “Rotation direction”, “Z phase output form”,
“ABZ output enabling / disabling”, “ABZ phase hysteresis” and “ABZ resolution”.
The register value is duplicated from corresponding memory after power on or, when the mode
transferred to "Normal Mode" from “User Mode”.
a) Rotation direction configuration: The output direction can be set in if the angle data increases
clockwise or clockwise (Refer to section 16). Relation between the rotation direction and RD is
as following.
Rotation Direction
R_RD
Default
CCW (+)
0x0
●
CW (-)
0x1
b)
Z phase output form configuration: The Z phase can be set as either among two modes.
One is a normal z phase output which carries out toggle at 0 degree position. The other is a
switch output which keeps low state in more than 180 degree and high state in less than 180
degree. (Refer to section 14.3 ABZ output figure)
Z phase output form
R_Z_MODE
Default
Normal output
0x0
●
Switch output
0x1
c) ABZ output enable configuration: It is possible to disable the ABZ output as necessary.
When the ABZ output is set to “inability (0x0)”, the output becomes Hi-Z.
ABZ Output State
R_ABZ_E
Default
ABZ Output Inability
0x0
（Hi-Z output）
ABZ Output
0x1
●
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d) ABZ hysteresis configuration: This configuration can be used to prevent unexpected ABZ
pulses under noise influence. Relation between ABZ hysteresis and ABZ_HYS set value is as
following.
ABZ Hysteresis
R_ABZ_HYS[2:0]
Default
Invalid
0x0
0LSB
0x1
1LSB
0x2, 0x5, 0x6, 0x7
●
2LSB
0x3
3LSB
0x4
Figure 7. Operational Overview of Hysteresis Configuration
Note 13. As to the difference of ABZ hysteresis between “0LSB” and “Invalid”;
Internal angle data always alternates between two adjacent angle data because of the tracking loop
characteristics even if the environment is a static condition.
In “Invalid” configuration, ABZ output is reflected by internal angle data directly.
But in “0LSB” configuration, ABZ output is reflected by internal angle data when internal angle data
change over two consecutive LSB in same rotation direction.
Thus in this case, LSB bit alternation caused by noise is masked from ABZ output.
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e) ABZ output resolution configuration: Able to configure the ABZ resolution. Relation between
ABZ resolution and set value is as following.
ABZ phase resolution
R_ABZ_RES[D3:0]
Default
1024ppr
0x0
●
512ppr
0x1
256ppr
0x2
128ppr
0x3
1000ppr
0x4
900ppr
0x5
800ppr
0x6
700ppr
0x7
600ppr
0x8
500ppr
0x9
400ppr
0xA
360ppr
0xB
300ppr
0xC
200ppr
0xD
100ppr
0xE
50ppr
0xF
R_MLK Register (Register Address：0x08)
R_MLK
Content
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
R_MLK[1:0]
Register Function: This register is to be duplicated from data at the memory lock configuration
address on EEPROM. This address is read-only for confirming the memory lock state. Relation
between the memory lock state and MLK register value is as following.
Memory Lock State
Unlocked
Locked
R_MLK[1:0]
0x3
0x0, 0x1, 0x2
Default
●
R_EBDIS Register (Register Address : 0x09)
R_EBDIS
Content
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
R_EBDIS[1:0]
Register Function: This register is used for disabling / enabling each abnormal diagnosis function
as necessary. Relation between the diagnosis function and EBDIS is as following. Each bit have its
function, and “1” means DISABLE. The register value is duplicated from corresponding memory
after power on or, when the mode transferred to "Normal Mode" from “User Mode”.
Abnormal Diagnosis
Parameter
Magnetic Flux Density
Tracking Lost
Bit data
Default
R_EBDIS[1]
R_EBDIS[0]
0
0
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R_UVW Register (Register Address : 0x0A)
R_UVW
Content
D11
D10
D9
D8
D7
D6
D5
D4
D3
R_UVW_E R_UVW_HYS[2:0]
D2
D1
D0
R_UVW_RES[2:0]
Register Function: This register is used for configuring “UVW output enabling / disabling”, “UVW
phase hysteresis”, “the number of UVW pulses per a rotation”.
The register value is duplicated from corresponding memory after power on or, when the mode
transferred to "Normal Mode" from “User Mode”.
a) UVW output enable configuration: It is possible to disable the UVW output as necessary.
When the ABZ output is set to “inability (0x0)”, the output becomes Hi-Z.
UVW Output State
R_UVW_E
Default
UVW output Inability
0x0
(Hi-Z output)
UVW output
0x1
●
b) UVW hysteresis configuration: This configuration can be used to prevent unexpected UVW
pulses under noise influence. Relation between UVW hysteresis and UVW_HYS set value is as
following.
UVW Hysteresis
R_UVW_HYS[2:0]
Default
Invalid
0x0
0LSB
0x1
1LSB
0x2, 0x5, 0x6, 0x7
●
2LSB
0x3
3LSB
0x4
c) The number of UVW pulses configuration: It is possible to set the number of UVW pulses per
a rotation by changing following bits according to the number of DCBL motor rotor’s magnetic
poles.
The number of
R_UVW_RES[2:0]
Default
UVW pulses
1ppr
0x0
2ppr
0x1
3ppr
0x2
●
4ppr
0x3
5ppr
0x4
6ppr
0x5
7ppr
0x6
8ppr
0x7
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● EEPROM Address Map
Table 13. EEPROM Memory Address Map
Addr.[HEX]
Memory
symbol
0x00
0x01
0x02
0x03
0x04
0x05
0x06
R/W Permission
Normal
Mode
User
Mode
E_ID1
E_ID2
E_ZP
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
R/W
R/W
R/W
0x07
E_RDABZ
N.A.
R/W
0x08
0x09
E_MLK
E_EBDIS
N.A.
N.A.
R/W
R/W
0x0A
E_UVW
N.A.
R/W
Note
For ID data
For ID data
For to set up angle zero point.
For set up “Rotation direction”, “Z
phase output form”, “ABZ output
enable/disable”, “ABZ Hysteresis” and
“ABZ resolution”.
For memory lock
For set up abnormal detection disable
For set up “UVW output
enable/disable”, “UVW Hysteresis”
and “UVW resolution”.
Note 14. Once set memory lock, this IC cannot be written to any memory.
Note 15. Each register value is duplicated from corresponding memory when the mode transferred to
"Normal Mode" or re-power on. In order to reflect a setup data on an output, please return to a normal
mode or re-power on.
● Each Memory Configurations
E_ID1 Memory (Memory Address：0x04)
E_ID1
Content
D11
D10
D9
D8
D7
D6
D5
E_ID1[11:0]
D4
D3
D2
D1
D0
Memory Function: This memory can be written as identification information or the lot information by the
IC user. Default value is 0x000.
E_ID2 Memory (Memory Address：0x05)
E_ID2
Content
D11
D10
D9
D8
D7
D6
D5
E_ID2[11:0]
D4
D3
D2
D1
D0
Memory Function: This memory can be written as identification information or the lot information
by the IC user. Default value is 0x000.
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E_ZP Memory (Memory Address：0x06)
E_ZP
Content
D11
D10
D9
D8
D7
D6
D5
E_ZP[11:0]
D4
D3
D2
D1
D0
Memory Function: This memory is available for setting arbitrarily angle position as zero position.
Relation between the angle position and the ZP data is the following.
Zero Point Angle
Position [°]
0
（360÷4096）×1
（360÷4096）×2
（360÷4096）×3
：
（360÷4096）×4095
E_ZP[11:0]
Default
0x000
0x001
0x002
0x003
：
0xFFF
●
Note 16. A setup of this register and memory is reflected in ABZ and UVW output.
E_RDABZ Memory (Memory Address：0x07)
E_RDABZ
Content
D11
D10
D9
D8
D7
D6 D5
D4
E_RD E_Z_MODE E_ABZ_E E_ABZ_HYS[2:0]
D3
D2
D1
D0
E_ABZ_RES[3:0]
Memory Function: This register is used for configuring “Rotation direction”, “Z phase output form”,
“ABZ output enabling / disabling”, “ABZ phase hysteresis” and “ABZ resolution”.
Relation between each bit and setting value is as following.
a) Rotation direction configuration: The output direction can be set in if the angle data increases
clockwise or clockwise (Refer to section 16). Relation between the rotation direction and RD is
as following.
Rotation Direction
E_RD
Default
CCW (+)
0x0
●
CW (-)
0x1
b) Z phase output form configuration: The Z phase can be set as either among two modes One
is a normal z phase output which carries out toggle at 0 degree position. The other is a switch
output which keeps low state in more than 180 degree and high state in less than 180 degree.
(Refer to section 14.3)
Z phase output form
E_Z_MODE
Default
Normal output
0x0
●
Switch output
0x1
c) ABZ output enable configuration: It is possible to disable the ABZ output as necessary.
When the ABZ output is set to “inability (0x0)”, the output becomes Hi-Z.
ABZ Output State
E_ABZ_E
Default
ABZ Output Inability
0x0
（Hi-Z output）
ABZ Output
0x1
●
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d) ABZ hysteresis configuration: This configuration can be used to prevent unexpected ABZ
pulses under noise influence. Relation between ABZ hysteresis and ABZ_HYS set value is as
following.
ABZ Hysteresis
E_ABZ_HYS[2:0]
Default
Invalid
0x0
0LSB
0x1
1LSB
0x2, 0x5, 0x6, 0x7
●
2LSB
0x3
3LSB
0x4
Figure 8. Operational Overview of Hysteresis Configuration
Note 17. As to the difference of ABZ hysteresis between “0LSB” and “Invalid”;
Internal angle data always alternates between two adjacent angle data because of the tracking loop
characteristics even if the environment is a static condition.
In “Invalid” configuration, ABZ output is reflected by internal angle data directly.
But in “0LSB” configuration, ABZ output is reflected by internal angle data when internal angle data
change over two consecutive LSB in same rotation direction.
Thus in this case, LSB bit alternation caused by noise is masked from ABZ output.
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e) ABZ output resolution configuration: Able to configure the ABZ resolution by using this
configuration. Relation between ABZ resolution and set value is as following.
ABZ phase resolution
ABZ_RES[3:0]
Default
1024ppr
0x0
●
512ppr
0x1
256ppr
0x2
128ppr
0x3
1000ppr
0x4
900ppr
0x5
800ppr
0x6
700ppr
0x7
600ppr
0x8
500ppr
0x9
400ppr
0xA
360ppr
0xB
300ppr
0xC
200ppr
0xD
100ppr
0xE
50ppr
0xF
E_MLK Memory (Memory Address：0x08)
E_MLK
Content
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
E_MLK[1:0]
Memory Function: This configuration is used for locking the memory.
By writing data [0x00] (except for 0x03) in address [0x08], the memory lock is executed. Once the
memory is locked, all memory data cannot be changed, and also the memory lock function cannot
be released.
Memory Lock State
Unlocked
Locked
E_MLK[1:0]
0x3
0x0, 0x1, 0x2
Default
●
E_EBDIS Memory (Memory Address : 0x09)
E_EBDIS
Content
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
E_EBDIS[1:0]
Memory Function: This memory is used for disabling / enabling each abnormal diagnosis function
as necessary. Relation between the diagnosis function and EBDIS is as following. By writing 1 in a
corresponding bit, the abnormal diagnosis function is disabled.
Abnormal Diagnosis
Parameter
Magnetic Flux Density
Tracking Lost
Bit data
Default
E_EBDIS[1]
E_EBDIS[0]
0
0
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E_UVW Memory (Memory Address : 0x0A)
E_UVW
Content
D11
D10
D9
D8
D7
D6
D5
D4
D3
E_UVW_E E_UVW_HYS[2:0]
D2
D1
D0
E_UVW_RES[2:0]
Memory Function: This memory is used for configuring “UVW output enabling / disabling”, “UVW
phase hysteresis”, “the number of UVW pulses per a rotation”. Relation between each bit and
setting value is as following.
a) UVW output enable configuration: It is possible to disable the UVW output as necessary.
When the ABZ output is set to “inability (0x0)”, the output becomes Hi-Z.
UVW Output State
E_UVW_E
Default
UVW output Inability
0x0
(Hi-Z output)
UVW output
0x1
●
b) UVW hysteresis configuration: This configuration can be used to prevent unexpected UVW
pulses under noise influence. Relation between UVW hysteresis and UVW_HYS set value is as
following.
UVW Hysteresis
E_UVW_HYS[2:0]
Default
Invalid
0x0
0LSB
0x1
1LSB
0x2, 0x5, 0x6, 0x7
●
2LSB
0x3
3LSB
0x4
c) The number of UVW pulses configuration: It is possible to set the number of UVW pulses per
a rotation by changing following bits according to the number of DCBL motor rotor’s magnetic
poles.
The number of
E_UVW_RES[2:0]
Default
UVW pulses
1ppr
0x0
2ppr
0x1
3ppr
0x2
●
4ppr
0x3
5ppr
0x4
6ppr
0x5
7ppr
0x6
8ppr
0x7
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16. ABZ Output Figure
The ABZ output is following figure; The A and B are 1024pulses and Z pulse is outputted with one pulse
during a rotation. (The number of A and B pulse is settable via SPI.). Moreover, the Z phase can be set to
“Normal Output” which toggle at 0 degree position and “Switch Output” which keeps low state in more
than 180 degree and high state in less than 180 degree.
B
B
A
A
Z
Z
360°(4096 code)
180°(2048 code)
360°(4096 code)
Z phase normal output
selection
Figure 9. ABZ Output figure
Z phase switch output
selection
Note 28. Z-phase Output corresponds to the Zero point configuration which should be set by user.
The ABZ output is generated by the bit operation from 12 bit absolute angle data.
In order to generate the ABZ output, the angle data ANG[11:0] is once changed into ANG_ABZ[11:0] by
the following operation.
ANG_ABZ[11:0] = absolute angle data ANG[11:0] × (ABZ resolution set value ABZ_RES[ppr] ×4 ) ÷ 4096
Then, From obtained ANG_ABZ[11:0], the A phase is generated by Bit1, and B phase is generated by
Bit1 Bit0. Z phase is generated by NOR all 12bit data.
Note 19. When the ABZ output is except a exponentiation setup of 2, the angle linearity error
deteriorates in range of -1 to 0 LSB(-0.088 to 0 degree.).
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17. UVW Output Figure
This is a function which outputs the UVW signal which is needed for a DCBL motor drive. The UVW
output can be set in the range of 1-8 pulses to one rotation. Moreover, U, V and W signal has 120 degree
phase difference in an electric angle respectively. The zero point setup is reflected to start position of
UVW.
Regarding the zero point setup, see the “ZP Register/Memory” setup in section 14.
U
V
W
Rotatio
n Angle 0
60
120
180
240
300
360
300
360
In case of 1 pulse setup
U
V
W
Rotatio
n Angle
0
60
120
180
240
In case of 2 pulse setup
Figure 10. UVW Output figure
If there is difference between UVW and ABZ hysteresis, the start position of UVW phase shifts by the
difference of UVW and ABZ hysteresis setup.
In order to generate the UVW output, the angle data ANG[11:0] is once changed into ANG_UVW[5:0] by
the following operation.
ANG_UVW[5:0] = absolute angle data ANG[11:0] × (the number of UVW pulse set value UVW_RES[ppr]
×6 ) ÷ 4096
By using obtained ANG_UVW[5:0], each U, V and W phase signal is generated as following.
U : When ANG_UVW [5:0] value is from 6N to 6N+2, an output is high-level, and it is a low level when
other.
V : When ANG_UVW [5:0] value is from 6N+2 to 6N+4, an output is high-level, and it is a low level when
other.
W : When ANG_UVW [5:0] value is from 6N+1 to 6N+3, an output is low-level, and it is a High level when
other.
Here, N means the order of output pulses. (from 0 to the number of pulses -1).
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18. Abnormal Detection Functions
This IC detects an abnormal state and indicates an abnormal state via ERROR PIN and serial interface.
Abnormal state is outputted at the angle output timing after 2.7ms(Typ) delay after detecting abnormal
state.
1) Abnormal Detection Items
●Magnetic Flux Density Range Error
When IC is applied in less than 10mT(Typ), the abnormal state is detected.
●Tracking Lost
If the angle error in the tracking by the type 2 servo is greater than or equal to 2°, it will be tracking
lost state (if the lock state is out due to type 2 servo). Because it is not overlooking the accurate
absolute angle output in this state, it will be the anomaly detection state. Also monitoring of the
abnormal state is every 2.56ms (Typ).
2) Output state in abnormal
The output is as following during abnormal state.
・ABZ and UVW Output
ABZ and UVW signal is outputted even if during abnormal state but the data may not be correct.
・SPI Output
The parity bits(P1 and P2 bit) and error bit is outputted as following.
Normal State
Abnormal State
P1 bit
ODD parity
EVEN parity
P2 bit
ODD parity
EVEN parity
E bit
1
0
・ERROR PIN Output
Output is low in abnormal state (high in normal state). The updating cycle of Error pin output is
every 80µs(Typ.).
Note 20. When the abnormal state is released, IC returns to the normal output state automatically.
Note 21. In User mode, output on ERROR PIN is low state.
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19. Angle Zero Position at Shipment,
and Relation between Magnet Angle Position and Output
The relation between magnet angle position over the package and angle output data is as following
in Configuration at shipment (Zero Point configuration: default).
The relation between the angle output of the following figure, a package, and a magnet position has
a few degree error.
When the relation between an angle output and a magnet position correctly has to be decided, use
a zero point setup.
0°
N
N
S
90°
S
Figure 11. Relationship of Magnet position and the angle output at factory default setting
● Relation between Angle Position and Serial Angle Data
Relation between angle position and serial angle data is as following. When the zero point is
configured, the zero point is the angle position 0°.
Angle Position [°]
0
(360÷4096)× 1
(360÷4096)× 2
(360÷4096)× 3
:
(360÷4096)× 4095
Angle Data
0x000
0x001
0x002
0x003
:
0xFFF
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20. Package Information
20.1. Outline Dimensions
Figure 12. Package outline drawing
□ Sensor Position Information
Sensor area
Accuracy
センサー位置精度
0.2 mm
Sensor
センサー
Top View
Sensor Position Information
The sensing area is embedded to the center of
the PKG plane with 0.2mm allowance.
And the depth is 0.55mm(typ.) from PKG surface.
The angle sensor needs to align the center of
magnet and sensing area and rotation axis.
Sensor area
センサー位置精度
Accuracy
0.55 ± 0.1
Sensor
センサー
area
Sectional View
Figure 13. Sensor Position
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20.2. Marking
Production information is printed on the package surface by laser marking.
Product Name
AK7451
Year (Last Digit)
Week
Production Control Code
Production Control Code
Production Control Code
AK7451
1637EAU
YY WW X X X
Figure14. Marking Information
Pin #1 Indication
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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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湘ICP备2023018690号
