AKM AK7401 Rotary position sensor ic Datasheet

[AK7401]
AK7401
Rotary Position Sensor IC
1.
General Description
The AK7401 is a monolithic Hall-Effect sensor IC that specializes in detecting rotation angle. A
contactless rotary position sensor is easily designed with a magnet.
The AK7401 is only sensitive to the magnetic flux density applied parallel to the IC surface. This is
obtained through a magnetic concentrator which is mounted on the Hall-Effect elements. It is
advantageous to accurate angular measurements against mechanical displacement.
To detect the rotation angle of a magnet, the AK7401 provides a 12-bit angle data. The angle data output
is available via PWM and serial data protocols.
2.
Applications
Steering wheel position sensor, Pedal position sensor, Throttle position sensor, EGR valve position
sensor, Turbo valve position sensor, Motor shaft position sensor
3.
Features
□
□
□
□
□
□
□
□
□
360° Contactless Angle Sensor
Angle Resolution : 12bit
Angle Linearity Error: ±0.95°@25°C
Over Voltage Protection: +16V @VDD pin
Reverse Voltage Protection: -16V @VDD, VSS pin
Automotive Temperature Range: -40°C to +150°C
AEC-Q100 Compliant
Output Interface: 3-wire SPI / PWM Push-Pull / PWM NMOS Open-Drain
User Programmable
□ Zero degree point
□ Magnet rotation direction: CCW or CW
□ Angle data average: OFF, SPC (2 times average), HP (8 times average)
□ PWM frequency: 250, 500 and 1000Hz
□ PWM polarity
□ OUT pin output type: Push-Pull / NMOS Open-Drain
□ Self-diagnostic Functions
□ Mismatch detect function for triple-redundant EEPROM data
□ Under and over supply voltage detect function
□ Under and over magnetic flux density detect function
□ Environmental Friendly (RoHS Compliant)
□ Lead free
□ Halogen free
014002685-E-01
2015/07
-1-
[AK7401]
4.
Table of Contents
1.
General Description ......................................................................................................................... 1
2.
Applications ..................................................................................................................................... 1
3.
Features........................................................................................................................................... 1
4.
Table of Contents ............................................................................................................................ 2
5.
Functional Block Diagram ............................................................................................................... 3
6.
Pin Configuration ............................................................................................................................. 4
7.
Absolute Maximum Ratings............................................................................................................. 4
8.
EEPROM Characteristics ................................................................................................................ 5
9.
Operating Conditions....................................................................................................................... 5
10.
Electrical and Magnetic Characteristics .......................................................................................... 5
11.
Serial I/F Digital Characteristics ...................................................................................................... 6
12.
PWM Characteristics ....................................................................................................................... 7
13.
Supply Voltage Level Detection Characteristics ............................................................................. 8
14.
Programmable Mode Descriptions .................................................................................................. 9
15.
Serial I/F Protocol .......................................................................................................................... 11
16.
Self-diagnostic Function ................................................................................................................ 13
17.
Register & EEPROM Address Map &Description ......................................................................... 15
18.
Default Settings Information .......................................................................................................... 25
19.
Recommended External Circuit .................................................................................................... 26
20.
Package Information ..................................................................................................................... 27
■ Outline Dimensions ......................................................................................................................... 27
■ Materials .......................................................................................................................................... 27
■ Marking............................................................................................................................................ 28
■ Sensitive Area Location .................................................................................................................. 28
21.
Revision History............................................................................................................................. 28
014002685-E-01
2015/07
-2-
[AK7401]
5.
Functional Block Diagram
VDD
TEST0
Rev. Vol.
Protection
Overvoltage
Protection
Voltage
Regulator
POR
TEST1
Diagnostic
HE-X
Chopper
Switch
INT(X)
HE-Y
INT(Y)
PreAmp
Angle
Detection
OSC
Hall
Drive
EEPROM
PWM
Serial
I/F
Driven by VCORE
OUT
CS
SCLK
SIN/
SOUT
VSS
Figure 1. Functional Block Diagram
Block name
HE-X / HE-Y
Chopper Switch
PreAmp
Hall Drive
OSC
INT-X / Y
Angle Detection
PWM
Serial I/F
Rev. Vol. Protection
Overvoltage
Protection
Voltage Regulator
POR
EEPROM
Diagnostic
Table 1. Functional Block Description
Function
Detect the X/Y-compositions of the magnetic flux density applied
parallel to the IC package surface by a magnetic concentrator.
Switch the current direction in order to cancel the Hall elements
offset.
Amplify the signals from the Hall elements.
Drive the constant current for the Hall elements.
Generate master clock.
Integrate the amplified signals to reduce the noise.
Calculate the 12-bit angle data from the X/Y integrated signal.
Generate the PWM signal based on the 12-bit angle data.
Interface based on 3-wire serial protocol.
Protect the IC from the reverse connection to the power supply pin.
Protect the IC from an over voltage supply.
Regulate the internal bias voltage.
Generate a reset signal at the time of low supply voltage.
Non-volatile memory. The stored data is triply copied to the other
particular address automatically.
Detect the level of supply voltage, the level of the magnetic flux
density and a mismatch of the triple-redundant configuration
EEPROM data.
014002685-E-01
2015/07
-3-
[AK7401]
6.
Pin Configuration
Table 2. Pin Description
No.
Symbol
I/O
Type
Function
1
VDD
Power
Power Supply Pin
2
TEST0
Test Dedicated Pin (Note 1)
3
CS
I
Digital
Chip Select Signal Pin
4
SCLK
I
Digital
Serial Clock Signal Pin
5
OUT
O
Digital
PWM Output Pin
6
TEST1
Test Dedicated Pin (Note 1)
7
SIN/SOUT
I/O
Digital
Serial Input/Output Data Signal Pin
8
VSS
Power
Ground Pin
Note 1. The TEST0 and TEST1 pins must be open.
1
VDD
8
9
VSS
TEST0
SIN/SOUT
CS
TEST1
4
SCLK
5
OUT
Figure 2. Pin Configuration
7.
Absolute Maximum Ratings
Parameter
Symbol
Min.
Max.
Unit
Supply Voltage
VDD
-16
16
(Note 2)
V
Terminal Voltage 1
VTERM1
-0.3
VDD
(Note 2)
V
Terminal Voltage 2
VTERM2
-0.3
6
V
Notes
VDD, VSS pin
over voltage protection
reverse voltage protection
OUT, SIN/SOUT, CS, SCLK pin
VDD > VTERM1
TEST0, TEST1 pin
VDD > VTERM2
Output Current on
IOUT1
-10
10
mA
OUT pin
Output Current on
IOUT2
-1.25
1.25
mA
SIN/SOUT pin
Storage
Tstg
-50
+150
C
Temperature
Note 2. The values of VDD and VTERM1 are for instantaneous voltage by accident, are not for a constant
condition such as an operating condition.
WARNING: Operation at or beyond these limits may cause permanent damage to the device. Normal
operation is not guaranteed at these extremes.
014002685-E-01
2015/07
-4-
[AK7401]
8.
(VDD=4.0 to 5.5V)
Parameter
EEPROM
Endurance
Ambient
Temperature in
Writing
Writing Time
Symbol
EEPROM Characteristics
Min.
Typ.
Een
Taw
0
Tw
9.
Max.
Unit
1000
Cycle
+85
C
20
ms
Notes
This parameter is
guaranteed by design.
Operating Conditions
Parameter
Symbol
Min.
Typ.
Max.
Unit
Notes
Supply Voltage
VDD
4.0
5.0
5.5
V
Operating Ambient
Ta
-40
+150
C
Temperature
WARNING: Electrical and magnetic characteristics are not guaranteed when operated at or beyond
these conditions.
10. Electrical and Magnetic Characteristics
(Ta=-40 to +150C, VDD=4.0 to 5.5V; unless otherwise specified)
Parameter
Symbol
Conditions
Min.
Typ.
Max.
Unit
Magnetic Flux Density Range
BRANGE
20
50
70
mT
Angle Detection Range
ARANGE
0
359.9
Deg.
Angle Resolution
ARES
12bit
0.088
Deg.
Ta=25°C
Angle Linearity Error
AINL
-0.95
+0.95
Deg.
SPC,HP settings
Thermal Angle Drift
Caused by Sensitivity
HMXY
-0.45
+0.45
Deg.
Ta=25°C basis
Mismatch
SPC,HP settings
Thermal Angle Drift
ADCos
-0.18
+0.18
Deg.
Caused by ADC offset
1σ
Angle Output Noise
ANOISE
+0.2
Deg.
SPC settings
Angle Update Period
ACYCLE
100
110
μs
Supply Current
IDD
No output load
8
12
mA
Startup Time (Note 3)
TSTART
2.0
ms
Note 3. Startup time is defined as the time from when VDD reaches operating voltage level to when the
serial data connection is available.
014002685-E-01
2015/07
-5-
[AK7401]
11. Serial I/F Digital Characteristics
1) DC Characteristics
(Ta=-40 to +150C, VDD=4.0 to 5.5V; unless otherwise specified)
Parameter
Symbol
Conditions
Min.
Input High Level
VHSI
0.7VDD
Input Low Level
VLSI
Input Current
ISI
-10
Output High Level
VHSO
IOUT2=+400uA
0.8VDD
Output Low Level
VLSO
IOUT2=-700uA
-0.3
Typ.
0.3VDD
+10
0.2VDD
2) AC Characteristics
(Ta=-40 to +150C, VDD=4.0 to 5.5V; unless otherwise specified)
Parameter
Symbol
Conditions
Min.
SCLK High Time
TH
200
SCLK Low Time
TL
200
SCLK Rise Time
Tr
(Note 4)
SCLK Fall Time
Tf
(Note 4)
CS Setup Time
TCSS
100
CS Hold Time
TCSH
200
Data Setup Time
TDS
100
Data Hold Time
TDH
100
Cload=100pF,
Data Valid Time
TDV
no load current
Wait Time
TEW
EEPROM write time
20
Wait Time
TRW
Register write time
2.5
Note 4. This parameter is guaranteed by design.
Tr
Max.
Typ.
Unit
V
V
μA
V
V
Max.
Unit
ns
ns
30
ns
30
ns
ns
ns
ns
ns
200
ns
ms
μs
Tf
0.7VDD
SCLK
0.3VDD
TCSS
CS
SCLK
TCSH
TDS TDH
1
2
TL
23
TEW / TRW
TH
24
TDV
SIN/SOUT
OP3
OP2
D1
D0
Figure 3. Serial I/F AC Characteristics
014002685-E-01
2015/07
-6-
[AK7401]
12. PWM Characteristics
1) DC Characteristics
(Ta=-40 to +150C, VDD=4.0 to 5.5V; unless otherwise specified)
Parameter
Symbol
Conditions
Min.
Typ.
Output Low Level
VHP
5
IOUT＝-4mA
Output High Level VLP
90
95
IOUT＝4mA
PWM Output
RPWM
0.0195
Resolution
2) AC Characteristics
(Ta=-40 to +150C, VDD=4.0 to 5.5V; unless otherwise specified)
Parameter
Symbol
Conditions
Min.
Typ.
E_PWMF=0x3F
225
250
PWM Frequency
FPWM
E_PWMF=0x07
450
500
E_PWMF=0x00
900
1000
Push-Pull output
Rise Time
TrOUT
0.1
0.22
2.2nF, 10kΩ
Push-Pull output
Fall Time
TfOUT
Open drain output
0.2
0.47
2.2nF, 10kΩ
Open drain output
Rise Time
TrOUT
40
50
2.2nF, 10kΩ
PWM Jitter
JPWM
1σ
PWM polarity
9.9
10
Duty at 0°
positive
PWM polarity
89.9
90
Duty at 359.9°
positive
PWM polarity
89.9
90
Duty at 0°
negative
PWM polarity
9.9
10
Duty at 359.9°
negative
Max.
10
Unit
%VDD
%VDD
%DC/LSB
Max.
275
550
1100
Unit
Hz
Hz
Hz
0.6
μs
0.9
μs
60
μs
0.05
%DC
10.1
%DC
90.1
%DC
90.1
%DC
10.1
%DC
FPWM
VHP
angle 0°
duty 10%
VLP
angle 180°
duty 50%
angle 359.9°
duty 90%
Figure 4. Duty at Each Angle Position (PWM polarity positive case)
014002685-E-01
2015/07
-7-
[AK7401]
13. Supply Voltage Level Detection Characteristics
1) DC Characteristics
(Ta=-40 to +150C, unless otherwise specified)
Parameter
Symbol
Power-on Reset Release Level
V1
Under Voltage Detection Release Level
V2
Over Voltage Detection Level
V3
Output Shutdown Level
V4
Output Recovery Level
V5
Over Voltage Detection Release Level
V6
Under Voltage Detection Level
V7
Power-on Reset Level
V8
Conditions
Min.
2.75
3.45
5.8
6.9
6.15
5.55
3.3
2.3
Typ.
3.4
3.7
6.0
7.3
6.5
5.8
3.5
2.9
Max.
3.85
3.95
6.4
7.6
6.85
6.15
3.8
3.4
Unit
V
V
V
V
V
V
V
V
VDD [V]
16V
V4
V5
V3
V6
V2
V7
V1
V8
Figure 5. Supply Voltage Level Detection Diagram
014002685-E-01
2015/07
-8-
[AK7401]
14. Programmable Mode Descriptions
The AK7401 has the two operating modes (Normal Mode and User Mode). In User Mode, it is able to
read and write the internal registers and EEPROM according to a serial I/F. User Mode supports the
end-user programming such as zero point adjustment, magnet rotation direction, angle data averaging,
PWM frequency, PWM polarity and PWM output type.
When the power supply is turned ON, the AK7401 automatically resets the internal register and loads the
EEPROM configuration data to set the internal configuration register. After startup sequence, the
AK7401 operates in Normal Mode.
● Mode Description
Each mode can be changed by writing a specific OPCODE and DATA on a specific address as the
diagram below.
Normal Mode
ChangeMode
OPCODE: 0101
Addr. 0x02
DATA: 0x000
or
Restore power supply
or
Reset
OPCODE: 0110
Addr. 0x4E
ChangeMode
OPCODE: 0101
Addr. 0x02
DATA: 0x50F
User Mode
Figure 6. Operation Mode Transition Diagram
Mode Name
Normal Mode
Table 3. Operation Mode Description
Note
In Normal Mode, it is not able to access the internal register and EEPROM except
register R_ANG (Addr.0x00) and register R_CHMD (Addr.0x02). Available operation
codes are ReadAngle and ChangeMode.
The transmission time interval of ReadAngle operation code needs to be equal to
angle data update period or longer. If the interval time is shorter, R_ANG register is
not updated to the latest processing data.
In case of changing operation mode from User Mode to Normal Mode, all registers
are automatically initialized and loads the EEPROM configuration data to set the
internal configuration register.
014002685-E-01
2015/07
-9-
[AK7401]
User Mode
In User Mode, it is able to access the internal configuration register and EEPROM.
To set the following parameters in Normal Mode, configuration data need to be
stored in EEPROM.
1. Zero Degree Point
Configuration of the zero degree point defines the origin of the output angle
data. It is programmable at any angle position.
2.
Magnet Rotation Direction
Configuration of the magnet rotation direction defines the increase or
decrease of the output angle data relative to the magnet rotation direction.
When it is selected to CCW, the output angle data increases in response to
counter-clockwise direction magnet rotation.
3.
Angle Data Averaging
Configuration of angle data averaging provides OFF, SPC and HP settings.
In OFF setting, the AK7401 calculates the angle data without averaging
procedure. In SPC setting, the AK7401 calculates the angle data by 2 times
averaging. In HP setting, the AK7401 calculates the angle data by 8 times
averaging.
4.
PWM Frequency
Configuration of PWM frequency provides 250, 500 and 1000Hz settings.
5.
PWM Polarity
Configuration of PWM polarity provides plus and minus polarity settings. In
plus polarity settings, the highest angle data corresponds to maximum
PWM duty.
6.
OUT Pin Output Type
Configuration of the OUT pin output type provides Push-Pull and NMOS
Open-Drain.
7.
Magnetic Flux Density Detection Range
Configuration of magnetic flux density detection range provides under limit
setting and upper limit setting.
8.
Self-diagnostic Configuration
Configuration of self-diagnosis defines the activation or inactivation of each
self- diagnostic functions.
9.
Memory Lock
In order to prevent rewriting EEPROM incorrectly, it is able to lock the
memory. Once the configuration of memory lock is enabled, it is not
possible to change EEPROM anymore.
In User Mode, the OUT pin goes to high-impedance (Hi-Z) output.
Electrical and magnetic characteristics are not guaranteed in User Mode.
014002685-E-01
2015/07
- 10 -
[AK7401]
15. Serial I/F Protocol
Figure 7 shows timing chart on serial interface protocol. Data communication is only available when the
CS pin set to “H”. To write the internal register or EEPROM, serial data must be input via the SIN/SOUT
pin on the falling edge of SCLK. To read the internal register or EEPROM, the AK7401 outputs serial
data on the rising edge of SCLK.
<Write>
CS
SCLK
SIN/SOUT
1
*
2
3
OP2
OP3
4
OP1
5
OP0
6
A6
7
A5
8
A4
9
A3
10
A2
11
A1
12
A0
13
*
14
D11
22
D10
23
D2
24
D1
D0
*
Hi-Z
2
OPCODE(OP[3:0])：OP[3:0]=0001bin
<Read>
CS
SCLK
SIN/SOUT
1
*
2
OP3
3
OP2
4
OP1
5
OP0
6
A6
10
A5
A1
11
A0
12
13
Ｈｉ-Ｚ
14
D11
15
D10
D9
16
20
D8
D4
21
D3
22
D2
23
D1
24
D0
Hi-Z
OPCODE(OP[3:0])：OP[3:0]=0010bin
OPX:Operation Code
AX:Memory / Register Address
DX:Serial data
*:Don’t care
Figure 7. Serial I/F Timing Chart
●
OPCODE
Table 4. Operation Code Description
OPCODE
[3：0]
Code name
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
N/A
WriteEEPROM
ReadEEPROM
WriteReg
ReadReg
ChangeMode
Reset
N/A
N/A
ReadAngle
N/A
N/A
N/A
N/A
N/A
N/A
Description
N/A
Stores data to EEPROM
Reads data from EEPROM
Stores data to the internal register
Reads the internal register data
Changes operating mode
Restarts the AK7401
N/A
N/A
Reads the angle data
N/A
N/A
N/A
N/A
N/A
N/A
014002685-E-01
Accessibility
Normal
User
Mode
Mode
invalid
invalid
invalid
valid
invalid
valid
invalid
valid
invalid
valid
valid
valid
invalid
valid
invalid
invalid
invalid
invalid
valid
valid
invalid
invalid
invalid
invalid
invalid
invalid
invalid
invalid
invalid
invalid
invalid
invalid
2015/07
- 11 -
[AK7401]
●
Data sequence
1) Store Data
23
22 21 20 19 18 17 16 15 14 13 12 11 10 9
OP[3:0]
ADDR[6:0]
*
OP[3:0]: “0001” (to EEPROM), “0011”(to Register)
ADDR[6:0]: Register or EEPROM address number(See Address map)
DATA[11:0]: 12-bit data to store
(*: Don’t care)
8
7 6 5 4
DATA[11:0]
3
2
1
0
The configuration of EEPROM data has triple redundancy. When a data is written to a specific EEPROM
address (0x03 to 0x0B, 0x0D) via WriteEEPROM operation code, the stored data is triply copied to other
particular address automatically.
2) Read Data
23
22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4
OP[3:0]
ADDR[6:0]
Z
DATA[11:0]
OP[3:0]: “0010” (from EEPROM), “0100” (from Register)
ADDR[6:0]: Register or EEPROM address number (See Address map)
DATA[11:0]: 12-bit data to read
Z: Hi-Z
3
2
1
0
3
2
1
0
7 6 5 4 3
R_CHMD[11:0]
2
1
0
2
1
0
3) Read Angle Data
23 22 21 20 19 18 17 16
1
0
0
1
*
OP[3:0]: “1001”
R_ANG[11:0]: 12-bit angle data
P1: Parity bit for R_ANG[11:6]
P2: Parity bit for R_ANG[5:0]
E: Error bit for all valid self-diagnosis
Z: Hi-Z
(*: Don’t care)
15
Z
14
P1
13
P2
12
E
11
10
9
8
23 22 21 20 19 18 17 16 15 14 13 12 11 10
0
1
0
1
0
0
0
0
0
1
0
*
OP[3:0]: “0101”
ADDR[6:0]: “0x02”
R_CHMD[11:0]: “0x50F” (User Mode), “0x000” (Normal Mode)
(*: Don’t care)
9
8
9
8
7 6 5 4
R_ANG[11:0]
4) Change Mode
5) Soft Reset
23 22 21 20 19
0
1
1
0
1
OP[3:0]: “0110”
ADDR[6:0]: “0x4E”
(*: Don’t care)
18
0
17
0
16
1
15
1
14
1
13
0
12
014002685-E-01
11
10
7
6
5
4
3
*
2015/07
- 12 -
[AK7401]
16. Self-diagnostic Function
The AK7401 has several self-diagnostic functions to detect a function failure, a mismatch of EEPROM
data and an out-of-range operating condition. In User Mode, each diagnostic function can be disabled
but it is strongly recommended to enable all diagnostic functions for the system robustness.
●
Startup Sequence Diagnostic Function
The AK7401 indicates an error during the startup sequence. This error sets the PWM output to low
level and error bit to “0”.
●
Mismatch Detection among EEPROM Data
The AK7401 indicates an error when there is a mismatch of the triple-redundant configuration
EEPROM data. This error sets the PWM output to low level and error bit to “0”.
●
Mismatch Detection between Transfer Buffer Register and EEPROM Data
The AK7401 indicates an error when there is a mismatch between the transfer buffer register and the
EEPROM data. This error sets the PWM output to low level and error bit to “0”.
●
Mismatch Detection between Configuration Register and Transfer Buffer Register
The AK7401 indicates an error when there is a mismatch between the configuration register and the
transfer buffer register. This error sets the PWM output to low level and error bit to “0”.
●
Analog Signal Sequence Diagnostic Function
The AK7401 indicates an error when there is a failure in analog signal processing sequence. This
error sets the PWM output to low level and error bit to “0”.
●
Under or Over Magnetic Flux Density Detection
The AK7401 indicates an error when the magnetic flux density is undersupplied (default setting Typ.
B<5mT) or oversupplied (default setting Typ. B>80mT). This error sets the PWM output to low level
and error bit to “0”.
●
PWM Duty Over Range Diagnostic Function
The AK7401 indicates an error when there is a deviation from the normal duty cycle range (10 to
90%). This error sets the PWM output to low level.
●
Configuration Register Reloading Sequence Diagnostic Function
The AK7401 indicates an error when there is a failure in reloading sequence for the configuration
register from EEPROM. This error sets the PWM output to low level and error bit to “0”.
014002685-E-01
2015/07
- 13 -
[AK7401]
●
Averaging Data range Diagnostic Function
The AK7401 indicates an error when the original data set before averaging spread out among three
quadrants. This error sets the PWM output level to low and error bit to “0”.
It is caused by higher rotation speed than averaging time.
Quadrant 2
Quadrant 1
Quadrant 1
Quadrant 2
4
3
1
2
5
1
6
2
7
Quadrant 3
Quadrant 4
Quadrant 3
8
Quadrant 4
(a) In Case of Moving Average Filter SPC
(b) In Case of Moving Average Filter HP
Figure 8. Example of Error Diagnosis for Spreading Data Set
Quadrant2
2
Quadrant1
Quadrant1
Quadrant2
5
1
6
4
3
7
2
8
Quadrant3
Quadrant4
Quadrant3
1
Quadrant4
(a) In Case of Moving Average Filter SPC
(b) In Case of Moving Average Filter HP
Figure 9. Example of No-error Diagnosis for Spreading Data Set
014002685-E-01
2015/07
- 14 -
[AK7401]
●
EEPROM Write Sequence Diagnostic Function
The AK7401 indicates an error when there is overtime in the loading sequence for EEPROM (Typ.
6.4ms). This error sets the PWM output to low level and error bit to “0”.
●
Under or Over Voltage Supply Detection
The AK7401 indicates an error when supply voltage is less than under voltage detection level (Typ.
VDD<3.5V) or supply voltage is more than over voltage detection level (Typ. VDD>6.0V). This error
sets the PWM output to low level and error bit to “0”.
●
Excessive Over Voltage Supply Detection
The AK7401 indicates an error when supply voltage is more than output shutdown level (Typ.
VDD>7.3V). This error sets the PWM output to high impedance (Hi-Z) and error bit to “0”.
17. Register & EEPROM Address Map &Description
●
Register Address Map
Address
Register Name
0x00
0x01
0x02
0x03
0x04
0x05
0x06
0x07
0x08
0x09
Permission
Normal
User
Mode
Mode
R
R
N/A
R
W
R/W
N/A
R
N/A
R/W
N/A
R/W
N/A
R/W
N/A
R/W
N/A
R/W
R/W
N/A
Content
R_ANG[11:0]
Angle Data
R_MFDI[7:0]
Magnetic Flux Density Data
R_CHMD[11:0]
Mode Indicator
R_MLK[11:0]
Memory Lock Indicator
R_ID[11:0]
Free Bits for User
R_RD[2:0]
Rotation Direction Configuration
R_ZP[11:0]
Zero Degree Point Configuration
R_ABNRM[11:0]
Self-diagnostic Configuration
R_MFDRH[7:0]
Upper Limit of Magnetic Flux Density
R_MFDRL[7:0]
Lower Limit of Magnetic Flux Density
R_PWMPL[8:6]
PWM Polarity Configuration
0x0A
N/A
R/W
R_PWMF[5:0]
PWM Frequency Configuration
0x0B
R_PWMOMD[2:0]
N/A
R/W
Output Type of the OUT Pin Configuration
0x0C
N/A
N/A
N/A
0x0D
R_IT[8:3]
N/A
R/W
Angle Data Averaging Configuration
(N/A: not available, R: read only, W: write only, R/W: full access)
014002685-E-01
2015/07
- 15 -
[AK7401]
●
Register description
1) R_ANG (Addr. 0x00)
11
10
9
8
7
DATA[11:0]
6
5
R_ANG[11:0]
4
3
2
1
0
These registers contain the 12-bit angle data. In Normal Mode, R_ANG can be read via ReadAngle
operation code.
2) R_MFDI (Addr. 0x01)
11
10
9
8
7
DATA[11:0]
6
5
-
4
3
R_MFDI[7:0]
2
1
0
These registers contain the 8-bit magnetic flux density data. The data resolution is about 1mT.
In User Mode, the magnetic flux density can be detected from these registers. When fabricating a rotary
position sensor module that uses a magnet and the AK7401, it is able to check the magnetic flux density
whether targeted strength is applied or not.
3) R_CHMD (Addr. 0x02)
11
10
9
8
7
DATA[11:0]
6
5
R_CHMD[11:0]
4
3
2
1
0
These registers contain the 12-bit mode indication data. In Normal Mode, the mode indication data can
be stored in R_CHMD via ChangeMode operation code.
Operating
Mode
Normal
Mode
User Mode
R_CHMD[11:0]
Default
0x000
●
0x50F
014002685-E-01
2015/07
- 16 -
[AK7401]
4) R_MLK (Addr. 0x03)
11
10
9
8
7
DATA[11:0]
6
5
R_MLK[11:0]
4
3
2
1
0
These registers contain the 12-bit memory lock indication data. To check the memory condition, R_MLK
can be read via ReadReg operation code in User Mode.
Memory
Condition
Unlocked
Locked
R_MLK[11:0]
Default
Except for 0x5A5
0x5A5
●
5) R_ID(Addr. 0x04)
11
10
9
8
7
DATA[11:0]
6
5
R_ID[11:0]
4
3
2
1
0
These registers contain the 12-bit identification data which is stored in EEPROM for user traceability
purpose.
6) R_RD (Addr. 0x05)
11
10
9
8
7
-
DATA[11:0]
6
5
4
3
2
1
R_RD[2:0]
0
These registers contain the configuration data of magnet rotation direction.
CCW (counter clockwise) is defined by the 1-4-5-8 pin order direction for SOP-8 package top view
position.
CW (clockwise) is defined by the 8-5-4-1 pin order direction for SOP-8 package top view position.
Rotation
Direction
CCW
CW
R_RD[2:0]
Default
0x0
0x7
●
7) R_ZP (Addr. 0x06)
11
10
9
8
7
DATA[11:0]
6
5
R_ZP[11:0]
4
3
2
1
0
These registers contain the configuration data of zero degree point. This data is used as a reference of
the 12-bits angle data.
014002685-E-01
2015/07
- 17 -
[AK7401]
8) R_ABNRM (Addr. 0x07)
11
10
9
8
7
DATA[11:0]
6
5
R_ABNRM[11:0]
4
3
2
1
0
These registers contain the configuration data for the self-diagnostic functions. To disable a specific
diagnostic function, the corresponding bit should be set to “1”.
R_ABNRM[11:0]
R_ABNRM[11]
R_ABNRM[10]
R_ABNRM[9]
R_ABNRM[8]
R_ABNRM[7]
R_ABNRM[6]
R_ABNRM[5]
R_ABNRM[4]
R_ABNRM[3]
R_ABNRM[2]
R_ABNRM[1]
R_ABNRM[0]
Description
Default
Diagnostic for over excessive voltage supply
Diagnostic for over or under voltage supply
Diagnostic for EEPROM write sequence
Diagnostic for dispersion of averaging data set
Diagnostic for EEPROM reload sequence
Diagnostic for deviation from normal PWM duty cycle range
Diagnostic for over or under the magnetic flux density
Diagnostic for analog signal sequence
Diagnostic for mismatch between the configuration register and the
transfer buffer register
Diagnostic for mismatch between the transfer buffer register and
EEPROM
Diagnostic for mismatch among the triple-redundant EEPROM
Diagnostic for IC startup sequence
0
0
0
0
0
0
0
0
0
0
0
0
9) R_MFDRH (Addr. 0x08)
11
10
9
8
7
DATA[11:0]
6
5
-
4
3
R_MFDRH[7:0]
2
1
0
These registers contain the configuration data for upper limit of the magnetic flux density. This data is
used as a reference for the magnetic flux density diagnostics. The default setting is “0x50”
(approximately 80mT). The data resolution is about 1mT.
R_MFDRH level should be more than R_MFDRL level.
10) R_MFDRL(Addr. 0x09)
11
10
9
8
7
DATA[11:0]
6
5
-
4
3
R_MFDRL[7:0]
2
1
0
These registers contain the configuration data for lower limit of the magnetic flux density. This data is
used as a reference for the magnetic flux density diagnostics. The default setting is “0x05”
(approximately 5mT). The data resolution is about 1mT.
R_MFDRL level should be less than R_MFDRH level.
014002685-E-01
2015/07
- 18 -
[AK7401]
11) R_PWMF, R_PWMPL (Addr. 0x0A)
11
10
-
9
DATA[11:0]
8
7
6
5
R_PWMPL[2:0]
4
3
2
R_PWMF[5:0]
1
0
These registers contain the configuration data for PWM frequency and polarity.
In plus polarity, PWM duty increases according to angle data increase.
In minus polarity, PWM duty increases according to angle data decrease.
PWM Polarity
R_PWMPL[2:0]
Default
Plus
Minus
0x0
0x7
●
R_PWMF[5:0]
Default
0x00
0x07
0x3F
●
PWM Frequency
[Hz]
1000
500
250
12) R_PWMOMD (Addr. 0x0B)
11
10
9
8
7
-
DATA[11:0]
6
5
4
3
2
1
0
R_PWMOMD[2:0]
These registers contain the configuration data of the output type for the OUT pin.
The output type configuration of the OUT pin provides Push-pull and NMOS-open-drain.
PWM output type
R_PWMOMD[2:0]
Default
Push-pull
NMOS-open-drain
0x0
0x7
●
13) R_IT (Addr. 0x0D)
11
10
-
9
8
7
DATA[11:0]
6
5
R_IT[5:0]
4
3
2
1
-
0
These registers contain the configuration data for moving average filter.
The configuration of moving average filter provides SPC (2 times averaging), HP (8 times averaging)
and OFF (without averaging procedure).
Average filter
R_IT[5:0]
Default
SPC
HP
OFF
0x00
0x07
0x3F
●
014002685-E-01
2015/07
- 19 -
[AK7401]
●
EEPROM Address Map
Address
EEPROM Name
0x00
0x01
0x02
0x03
0x04
MEM_0[11:0]
MEM_1[11:0]
MEM_2[11:0]
E_MLK[11:0]
E_ID[11:0]
MEM_5[11:3]
E_RD[2:0]
E_ZP[11:0]
E_ABNRM[11:0]
MEM_8[11:8]
E_MFDRH[7:0]
MEM_9[11:8]
E_MFDRL[7:0]
MEM_A[11:9]
E_PWMPL[8:6]
E_PWMF[5:0]
MEM_B[11:3]
E_PWMOMD[2:0]
MEM_C[11:0]
MEM_D[11:9]
E_IT[8:3]
MEM_D[2:0]
0x05
0x06
0x07
0x08
0x09
0x0A
0x0B
0x0C
0x0D
Permission
Normal
User
Mode
Mode
N/A
N/A
N/A
R/W
R/W
N/A
R/W
R/W
R/W
N/A
R/W
N/A
N/A
R/W
N/A
R/W
R/W
N/A
R/W
N/A
N/A
R/W
N/A
Content
AKM reserved
AKM reserved
AKM reserved
Memory Lock Key
Free EEPROM for User
AKM reserved
Rotation Direction Configuration
Zero Degree Point Configuration
Self-diagnostic Configuration
AKM reserved
Upper Limit of Magnetic Flux Density
AKM reserved
Lower Limit of Magnetic Flux Density
AKM reserved
PWM Polarity Configuration
PWM Frequency Configuration
AKM reserved
Output Type of the OUT Pin Configuration
AKM reserved
AKM reserved
Angle Data Averaging Configuration
AKM reserved
0x0E
to
N/A
R
AKM reserved
0x3F
(N/A: not available, R: read only, W: write only, R/W: full access)
●
EEPROM Description
1) E_MLK (Addr. 0x03)
11
10
9
8
7
DATA[11:0]
6
5
E_MLK[11:0]
4
3
2
1
0
These EEPROM contain the 12-bit memory lock key data. To prevent EEPROM from rewriting incorrectly,
the memory lock key data can be stored in E_MLK via WriteEEPROM operation code in User Mode.
Memory
Condition
Unlocked
Locked
E_MLK[11:0]
Default
Except for 0x5A5
0x5A5
●(0x000)
014002685-E-01
2015/07
- 20 -
[AK7401]
2) E_ID(Addr. 0x04)
11
10
9
8
7
DATA[11:0]
6
5
E_ID[11:0]
4
3
2
1
0
4
3
2
1
E_RD[2:0]
0
These EEPROM can use freely for traceability purpose.
3) E_RD (Addr. 0x05)
11
10
9
8
7
-
DATA[11:0]
6
5
These EEPROM contain the configuration data for magnet rotation direction. To validate the user
configuration in Normal Mode, store the configuration data in E_RD via WriteEEPROM operational code
in User Mode.
CCW (counter clockwise) is defined by 1-4-5-8 pin order direction for SOP-8 package top view position.
CW (clockwise) is defined by 8-5-4-1 pin order direction for SOP-8 package top view position.
Rotation
E_RD[2:0]
Default
Direction
CCW
0x0
●
CW
0x7
WARNING: If data except “0x0” and “0x7” is set to E_RD[2:0], the rotation direction can not be
guaranteed.
4) E_ZP (Addr. 0x06)
11
10
9
8
7
DATA[11:0]
6
5
E_ZP[11:0]
4
3
2
1
0
These EEPROM contain the configuration data for the zero degree point. This data is used as a
reference of the 12-bit angle data. To validate the user configuration in Normal Mode, store the
configuration data in E_ZP via WriteEEPROM operation code in User Mode.
014002685-E-01
2015/07
- 21 -
[AK7401]
5) E_ABNRM (Addr. 0x07)
11
10
9
8
7
DATA[11:0]
6
5
E_ABNRM[11:0]
4
3
2
1
0
These EEPROM contain the configuration data for self-diagnostic functions. To inactivate a specific
diagnostic function, the corresponding bit should be set to “1”. To validate the user configuration in
Normal Mode, store the configuration data to E_ABNRM via WriteEEPROM operation code in User
Mode.
E_ABNRM[11:0]
E_ABNRM[11]
E_ABNRM[10]
E_ABNRM[9]
E_ABNRM[8]
E_ABNRM[7]
E_ABNRM[6]
E_ABNRM[5]
E_ABNRM[4]
E_ABNRM[3]
E_ABNRM[2]
E_ABNRM[1]
E_ABNRM[0]
Description
Diagnostic for over excessive voltage supply
Diagnostic for over or under voltage supply
Diagnostic for EEPROM write sequence
Diagnostic for dispersion of averaging data set
Diagnostic for EEPROM reload sequence
Diagnostic for deviation from normal PWM duty cycle range
Diagnostic for over or under the magnetic flux density supply
Diagnostic for analog signal sequence
Diagnostic for mismatch between the configuration register and the
transfer buffer register
Diagnostic for mismatch between the transfer buffer register and
EEPROM
Diagnostic for mismatch among the triple-redundant EEPROM
Diagnostic for IC startup sequence
014002685-E-01
Default
0
0
0
0
0
0
0
0
0
0
0
0
2015/07
- 22 -
[AK7401]
6) E_MFDRH (Addr. 0x08)
11
10
9
8
7
DATA[11:0]
6
5
-
4
3
E_MFDRH[7:0]
2
1
0
These EEPROM contain the configuration data for upper limit of the magnetic flux density. This data is
used as a reference for magnetic flux density diagnostics. To validate the user configuration in Normal
Mode, store the configuration data to E_MFDRH via WriteEEPROM operation code in User Mode. The
default setting is “0x50” (approximately 80mT). The data resolution is about 1mT.
E_MFDRH level should be more than E_MFDRL level.
7) E_MFDRL (Addr. 0x09)
11
10
9
8
7
DATA[11:0]
6
5
-
4
3
E_MFDRL[7:0]
2
1
0
These EEPROM contain the configuration data for upper limit of the magnetic flux density. This data is
used as a reference for magnetic flux density diagnostics. To validate the user configuration in Normal
Mode, store the configuration data to E_MFDRL via WriteEEPROM operation code in User Mode. The
default setting is “0x05” (approximately 05mT). The data resolution is about 1mT.
E_MFDRL level should be less than E_MFDRH level.
8) E_PWMF, E_PWMPL (Addr. 0x0A)
11
10
-
9
DATA[11:0]
8
7
6
5
E_PWMPL[2:0]
4
3
2
E_PWMF[5:0]
1
0
These EEPROM contain the configuration data for PWM frequency and polarity. To validate the user
configuration in Normal Mode, store the configuration data to E_PWMPL and E_PWMF via
WriteEEPROM operation code in User Mode.
In plus polarity, PWM duty increases according to angle data increase.
In minus polarity, PWM duty increases according to angle data decrease.
PWM Polarity
E_PWMPL[2:0]
Default
plus
0x0
●
minus
0x7
WARNING: If a data except “0x0” and “0x7” is set to E_PWMPL[2:0] bits, PWM polarity can not be
guaranteed.
PWM Frequency
E_PWMF[5:0]
Default
[Hz]
1000
0x00
●
500
0x07
250
0x3F
WARNING: If a data except “0x0”, “0x7” and “0x3F” is set to E_PWMF[5:0] bits, PWM frequency can not
be guaranteed.
014002685-E-01
2015/07
- 23 -
[AK7401]
9) E_PWMOMD (Addr. 0x0B)
11
10
9
8
7
-
DATA[11:0]
6
5
4
3
2
1
0
E_PWMOMD[2:0]
These EEPROM contain the configuration data of output type for the OUT pin. The output type
configuration of the OUT pin provides Push-pull and NMOS-open-drain. To validate the user
configuration in Normal Mode, store the configuration data to E_PWMOMD via WriteEEPROM operation
code in User Mode.
OUT pin output type
E_PWMOMD[2:0]
Default
Push-Pull
0x0
●
NMOS-Open-Drain
0x7
WARNING: If a data except “0x0” and “0x7” is set to E_PWMOMD[2:0] bits, the OUT pin output type can
not be guaranteed.
9) E_IT (Addr. 0x0D)
11
10
-
9
8
7
DATA[11:0]
6
5
E_IT[5:0]
4
3
2
1
-
0
These EEPROM contain the configuration data for the moving average filter of processing angle data.
The configuration of the moving average filter provides SPC (2 times averaging), HP (8 times averaging)
and OFF (without averaging procedure). To validate the user configuration in Normal Mode, store the
configuration data to E_IT via WriteEEPROM operation code in User Mode.
Average filter
E_IT[5:0]
Default
SPC
0x00
●
HP
0x07
OFF
0x3F
WARNING: If a data except “0x0”, “0x7” and “0x3F” is set to E_IT[5:0] bits, the moving average filter can
not be guaranteed.
014002685-E-01
2015/07
- 24 -
[AK7401]
18. Default Settings Information
The AK7401 default settings are as below.
1. Zero Degree Point
Figure 10 shows the default relationship between the magnet placement and the zero degree
point.
0°
8
8
5
N
S
S
N
1
5
N S
1
4
4
90°
Figure 10. Default Angle Setting
2. Magnet Rotation Direction
Figure 10. shows the default magnet rotation direction. The default setting is counter
clock-wise (CCW).
CCW is defined by the 1-4-5-8 pin order direction for SOP-8 package top view position.
3. Over and Under Magnetic Flux Density Limit
The default setting of upper limit of the magnetic flux density is approximately 80mT and under
limit is 5mT.
4. PWM Frequency
The default setting is 1000Hz.
5. PWM Polarity
The default setting is plus polarity.
In plus polarity settings, the highest angle data corresponds to maximum PWM duty.
6. Output Setting of the OUT Pin
The default setting is Push-Pull output type.
7. Self-diagnostic Configuration
The default setting is all valid diagnostic function.
8. Memory Lock
The default setting is unlocked.
014002685-E-01
2015/07
- 25 -
[AK7401]
19. Recommended External Circuit
It is recommended to use 100nF decoupling capacitors.
The TEST0 and TEST1 pins must be open.
When the 3-wire SPI interface is not used, the SCLK and CS pins must be connected to GND and the
SIN/SOUT pin must be open.
When PWM interface is not used, the OUT pin must be open.
100nF
SPI Master
8
1
VDD
VSS
VDD
AK7401
5V
SIN/SOUT
TEST0 SIN/SOUT
SIN/SOUT
TEST1
CS
SCLK
OUT
5
4
SCLK
SCLK
CS
VSS
CS
GND
GND
Figure 11. Recommended External Circuit for 3-wire SPI Connection
100nF
Duty cycle calculator
8
1
VDD
VSS
VDD
AK7401
5V
TEST0 SIN/SOUT
TEST1
CS
OUT
SCLK
OUT
OUT
5
4
Less than 2.2nF
VSS
GND
GND
Figure 12. Recommended External Circuit for PWM Connection
014002685-E-01
2015/07
- 26 -
[AK7401]
20. Package Information
■ Outline Dimensions
*
* Dimension does not include mold flush, protrusions or gate burrs.
■ Materials
Molding compound:
Lead frame material:
Outer lead plating:
Epoxy
Cu
Sn-2.5Ag
014002685-E-01
2015/07
- 27 -
[AK7401]
■ Marking
Year code
Week code(2 digits)
Lot number code
4 2 0
B A
2
1 A
7 4 0
4 2
7 4
0 B A
2
0 1 A
Assembly FAB code
Assembly ID code
Production code
■ Sensitive Area Location
Sensitive area
21. Revision History
Date (Y/M/D)
15/07/31
Revision
01
Reason
First Edition
Page
Contents
014002685-E-01
2015/07
- 28 -
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.