AK09911

[AK09911]
AK09911
3-axis Electronic Compass
1. Features


A 3-axis electronic compass IC with high sensitive Hall sensor technology.
Best adapted to pedestrian city navigation use for cell phone and other portable appliance.

Functions:
 3-axis magnetometer device suitable for compass application
 Built-in A to D Converter for magnetometer data out
 14-bit data out for each 3-axis magnetic component
 Sensitivity: 0.6 µT/LSB (typ.)
 Serial interface
 I2C bus interface
Standard, Fast and High-speed mode (up to 2.5 MHz) compliant with Philips I2C specification Ver.2.1
 Operation mode
 Power-down, Single measurement, Continuous measurement, Self-test and Fuse ROM access
 DRDY function for measurement data ready
 Magnetic sensor overflow monitor function
 Built-in oscillator for internal clock source
 Power on Reset circuit
 Self test function with internal magnetic source

Operating temperatures:

-30˚C to +85˚C
Operating supply voltage:
 Analog power supply
+2.4V to +3.6V
 Digital Interface supply
+1.65V to analog power supply voltage
Current consumption:
 Power-down:
3 µA (typ.)
 Measurement:
 Average current consumption at 100 Hz repetition rate: 2.4 mA (typ.)



Package:
 AK09911C
8-pin WL-CSP (BGA):
1.2 mm × 1.2 mm × 0.5 mm (typ.)
MS1526-E-01
2014/7
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[AK09911]
2. Overview
AK09911 is 3-axis electronic compass IC with high sensitive Hall sensor technology.
Small package of AK09911 incorporates magnetic sensors for detecting terrestrial magnetism in the X-axis, Y-axis, and
Z-axis, a sensor driving circuit, signal amplifier chain, and an arithmetic circuit for processing the signal from each sensor.
Self test function is also incorporated. From its compact foot print and thin package feature, it is suitable for map heading
up purpose in GPS-equipped cell phone to realize pedestrian navigation function.
AK09911 has the following features:
(1) Silicon monolithic Hall-effect magnetic sensor with magnetic concentrator realizes 3-axis magnetometer on a
silicon chip. Analog circuit, digital logic, power block and interface block are also integrated on a chip.
(2) Wide dynamic measurement range and high resolution with lower current consumption.
 Output data resolution:
14-bit (0.6 µT/LSB)
 Measurement range:
±4900 µT
 Average current at 100 Hz repetition rate:
2.4 mA (typ.)
(3) Digital serial interface
 I2C bus interface to control AK09911 functions and to read out the measured data by external CPU. A
dedicated power supply for I2C bus interface can work in low-voltage apply as low as 1.65V.
(4) DRDY register informs to system that measurement is end and set of data in registers are ready to be read.
(5) Device is worked by on-chip oscillator so no external clock source is necessary.
(6) Self test function with internal magnetic source to confirm magnetic sensor operation on end products.
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3. Table of Contents
1. Features ..............................................................................................................................1
2. Overview..............................................................................................................................2
3. Table of Contents.................................................................................................................3
4. Circuit Configration ..............................................................................................................5
4.1. Block Diagram ..............................................................................................................5
4.2. Block Function ..............................................................................................................5
4.3. Pin Function ..................................................................................................................6
5. Overall Characteristics ........................................................................................................7
5.1. Absolute Maximum Ratings ..........................................................................................7
5.2. Recommended Operating Conditions ..........................................................................7
5.3. Electrical Characteristics ..............................................................................................7
5.3.1. DC Characteristics .................................................................................................7
5.3.2. AC Characteristics .................................................................................................8
5.3.3. Analog Circuit Characteristics ................................................................................9
5.3.4. I2C Bus Interface ..................................................................................................10
6. Function Explanation .........................................................................................................13
6.1. Power States ...............................................................................................................13
6.2. Reset Functions ..........................................................................................................13
6.3. Operation Mode ..........................................................................................................14
6.4. Description of Each Operation Mode .........................................................................15
6.4.1. Power-down Mode ...............................................................................................15
6.4.2. Single Measurement Mode ..................................................................................15
6.4.3. Continuous Measurement Mode 1, 2, 3 and 4 ....................................................16
6.4.4. Self-test Mode ......................................................................................................19
6.4.5. Fuse ROM Access Mode .....................................................................................19
7. Serial Interface ..................................................................................................................20
7.1. Data Transfer ..............................................................................................................20
7.1.1. Change of Data ....................................................................................................20
7.1.2. Start/Stop Condition .............................................................................................20
7.1.3. Acknowledge ........................................................................................................21
7.1.4. Slave Address ......................................................................................................21
7.2. WRITE Instruction.......................................................................................................22
7.3. READ Instruction ........................................................................................................23
7.3.1. One Byte READ ...................................................................................................23
7.3.2. Multiple Byte READ .............................................................................................23
7.4. High-speed Mode (Hs-mode) .....................................................................................24
8. Registers ...........................................................................................................................25
8.1. Description of Registers .............................................................................................25
8.2. Register Map ..............................................................................................................26
8.3. Detailed of Description of Register .............................................................................27
8.3.1. WIA: Who I Am .....................................................................................................27
8.3.2. INFO: Information ................................................................................................27
8.3.3. ST1: Status 1........................................................................................................27
8.3.4. HXL to HZH: Measurement data..........................................................................28
8.3.5. TMPS: Dummy Register ......................................................................................28
8.3.6. ST2: Status 2........................................................................................................29
8.3.7. CNTL1: Dummy Register .....................................................................................29
8.3.8. CNTL2: Control 2 .................................................................................................29
8.3.9. CNTL3: Control 3 .................................................................................................30
8.3.10. TS1: Test ............................................................................................................30
8.3.11. ASAX, ASAY, ASAZ: Sensitivity Adjustment Values...........................................30
9. Example of Recommended External Connection .............................................................31
10. Package...........................................................................................................................32
10.1. Marking .....................................................................................................................32
10.2. Pin Assignment .........................................................................................................32
10.3. Outline Dimensions ..................................................................................................33
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10.4. Recommended Foot Print Pattern ............................................................................33
11. Relationsip between the Magnetic Field and Output Code .............................................34
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4. Circuit Configration
4.1. Block Diagram
3-axis
Hall
sensor
Chopper
SW
PreAMP
Integrator＆ADC
MUX
OSC
HE-Drive
SCL
Timing
Control
VREF
Interface Logic
& Register
SDA
RSTN
Magnetic source
POR
TST
CAD
VSS
VDD
FUSE ROM
VID
4.2. Block Function
Block
3-axis Hall sensor
MUX
Chopper SW
HE-Drive
Pre-AMP
Intergrator & ADC
OSC
POR
VREF
Interface Logic
&
Register
Timing Control
Magnetic Source
FUSE ROM
Function
Monolithic Hall elements.
Multiplexer for selecting Hall elements.
Performs chopping.
Magnetic sensor drive circuit for constant-current driving of sensor.
Fixed-gain differential amplifier used to amplify the magnetic sensor signal.
Integrates and amplifies pre-AMP output and performs analog-to-digital
conversion.
Generates an operating clock for sensor measurement.
Power On Reset circuit. Generates reset signal on rising edge of VDD.
Generates reference voltage and current.
Exchanges data with an external CPU.
I2C bus interface using two pins, namely, SCL and SDA. Standard, Fast and
High-speed modes are supported. The low-voltage specification can be supported
by applying 1.65V to the VID pin.
Generates a timing signal required for internal operation from a clock generated by
the OSC.
Generates magnetic field for self test of magnetic sensor.
Fuse for adjustment.
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4.3. Pin Function
Pin No.
Pin name
I/O
I
Power
supply
VDD
A1
A2
VDD
CAD
A3
Type
Power
CMOS
TST
I/O
VDD
CMOS
B1
B3
VSS
SCL
I
VID
Power
CMOS
C1
C2
VID
RSTN
I
VID
Power
CMOS
C3
SDA
I/O
VID
CMOS
Function
Positive power supply pin.
Slave address input pin.
Connect to VSS or VDD,
Test pin.
Pulled down by 100kΩ internal resister. Keep this pin
electrically non-connected.
Ground pin.
Control data clock input pin
Input: Schmidt trigger
Digital interface positive power supply pin.
Reset pin.
Resets registers by setting to “L”.
Control data input/output pin
Input: Schmidt trigger, Output: Open drain
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5. Overall Characteristics
5.1. Absolute Maximum Ratings
Vss=0V
Parameter
Power supply voltage
(Vdd, Vid)
Input voltage
Input current
Storage temperature
(Note 1)
Symbol
V+
Min.
-0.3
Max.
+4.3
Unit
V
VIN
IIN
Tst
-0.3
-40
（V+）+0.3
±10
+125
V
mA
˚C
If the device is used in conditions exceeding these values, the device may be destroyed. Normal operations are
not guaranteed in such exceeding conditions.
5.2. Recommended Operating Conditions
Vss=0V
Parameter
Operating temperature
Power supply voltage
Remark
VDD pin voltage
VID pin voltage
Symbol
Ta
Vdd
Vid
Min.
-30
2.4
1.65
Typ.
Max.
+85
3.6
Vdd
3.0
Unit
˚C
V
V
5.3. Electrical Characteristics
The following conditions apply unless otherwise noted:
Vdd=2.4V to 3.6V, Vid=1.65V to Vdd, Temperature range=-30˚C to 85˚C
5.3.1. DC Characteristics
Parameter
High level input voltage 1
Symbol
VIH1
Low level input voltage 1
VIL1
High level input voltage 2
Low level input voltage 2
Input current 1
VIH2
VIL2
IIN1
Input current 2
Hysteresis input voltage
(Note 2)
IIN2
VHS
Low level output voltage
(Note 3)
VOL
Current consumption
(Note 4)
IDD1
IDD2
IDD3
IDD4
Pin
RSTN
SCL
SDA
RSTN
SCL
SDA
TST
CAD
RSTN
SCL
SDA
CAD
TST
SCL
SDA
SDA
VDD
VID
Condition
Vin=Vss or Vid
Vin=Vss or Vdd
Vin=Vdd
Vid≥2V
Vid<2V
IOL≤+3mA
Vid≥2V
IOL≤+3mA
Vid<2V
Power-down mode
Vdd=Vid=3.0V
When magnetic sensor
is driven
Self-test mode
(Note 5)
MS1526-E-01
Min.
70%Vid
70%Vid
Typ.
Max.
Vid+0.3
Unit
V
-0.3
30%Vid
V
70%Vdd
-0.3
-10
Vdd+0.3
30%Vdd
+10
V
V
µA
-10
+10
100
5%Vid
10%Vid
0.4
µA
V
V
20%Vid
3
6
µA
3
6
mA
5
0.1
8
5
mA
µA
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[AK09911]
(Note 2)
(Note 3)
(Note 4)
(Note 5)
Schmitt trigger input (reference value for design)
Output is open-drain. Connect a pull-up resistor externally. Maximum capacitive load: 400pF (Capacitive load
of each bus line for I2C bus interface).
Without any resistance load. It does not include the current consumed by external loads (pull-down resister, etc.).
RSTN, SDA, SCL = Vid or 0V. CAD = Vdd or 0V.
(case 1) Vdd=ON, Vid=ON, RSTN pin = “L”. (case 2) Vdd=ON, Vid=OFF (0V), RSTN pin = “L”. (case 3)
Vdd=OFF (0V), Vid=ON.
5.3.2. AC Characteristics
Parameter
Power supply rise time
(Note 6)
POR completion time
(Note 6)
Power supply turn off
voltage (Note 6)
Power supply turn on
interval (Note 6)
Symbol
PSUP
Wait time before mode
setting
Twat
(Note 6)
(Note 7)
Pin
VDD
VID
PORT
SDV
PSINT
VDD
VID
VDD
VID
Condition
Period of time that VDD (VID)
changes from 0.2V to Vdd (Vid).
Period of time after PSUP to
Power-down mode (Note 7)
Turn off voltage to enable POR to
restart (Note 7)
Period of time that voltage lower
than SDV needed to be kept to
enable POR to restart (Note 7)
Min.
Typ.
Max.
50
Unit
ms
100
µs
0.2
V
100
µs
100
µs
Reference value for design.
When POR circuit detects the rise of VDD/VID voltage, it resets internal circuits and initializes the registers.
After reset, AK09911 transits to Power-down mode.
Power-down mode
Power-down mode
VDD/(VID)
PORT
SDV
0V
PSUP
Parameter
Reset input effective pulse width (“L”)
PSINT
Symbol
tRSTL
Pin
RSTN
Condition
Min.
5
Typ.
Max.
Unit
µs
tRSTL
VIL1
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5.3.3. Analog Circuit Characteristics
Parameter
Measurement data output bit
Time for measurement
Magnetic sensor sensitivity (Note 8)
Magnetic sensor measurement range
(Note 9)
Magnetic sensor initial offset
(Note 10)
Symbol
DBIT
TSM
BSE
BRG
Condition
Min.
-
Single measurement mode
Tc = 25 ˚C
0.57
Tc = 25 ˚C
±4912
Tc = 25 ˚C
-500
Typ.
14
7.2
0.6
Max.
8.5
0.63
Unit
bit
ms
µT/LSB
µT
+500
LSB
(Note 8) Value after sensitivity is adjusted using sensitivity fine adjustment data stored in Fuse ROM.
(Note 9) Reference value for design
(Note 10) Value of measurement data register on shipment without applying magnetic field on purpose.
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2
5.3.4. I C Bus Interface
I2C bus interface is compliant with Standard mode, Fast mode and High-speed mode. Standard/Fast mode is selected
automatically by fSCL.

Standard mode
fSCL≤100kHz
Symbol
fSCL
tHIGH
tLOW
tR
tF
tHD:STA
tSU:STA
tHD:DAT
tSU:DAT
tSU:STO
tBUF

Parameter
SCL clock frequency
SCL clock “High” time
SCL clock “Low” time
SDA and SCL rise time
SDA and SCL fall time
Start Condition hold time
Start Condition setup time
SDA hold time (vs. SCL falling edge)
SDA setup time (vs. SCL rising edge)
Stop Condition setup time
Bus free time
Min.
Typ.
Max.
100
4.0
4.7
1.0
0.3
4.0
4.7
0
250
4.0
4.7
Unit
kHz
µs
µs
µs
µs
µs
µs
µs
ns
µs
µs
Fast mode
100Hz≤fSCL≤400kHz
Symbol
fSCL
tHIGH
tLOW
tR
tF
tHD:STA
tSU:STA
tHD:DAT
tSU:DAT
tSU:STO
tBUF
tSP
Parameter
SCL clock frequency
SCL clock “High” time
SCL clock “Low” time
SDA and SCL rise time
SDA and SCL fall time
Start Condition hold time
Start Condition setup time
SDA hold time (vs. SCL falling edge)
SDA setup time (vs. SCL rising edge)
Stop Condition setup time
Bus free time
Noise suppression pulse width
Min.
Typ.
Max.
400
0.6
1.3
0.3
0.3
0.6
0.6
0
100
0.6
1.3
50
Unit
kHz
µs
µs
µs
µs
µs
µs
µs
ns
µs
µs
ns
[I2C bus interface timing]
1/fSCL
VIH1
SCL
VIL1
VIH1
SDA
VIL1
tLOW
tBUF
tR
tHIGH
tF
tSP
VIH1
SCL
VIL1
tHD:STA
Stop
Start
tHD:DAT
tSU:DAT
tSU:STA
tSU:STO
Start
Stop
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
High-speed mode (Hs-mode)
 Cb≤100pF (Cb: load capacitance)
fSCLH≤2.5MHz
Symbol
fSCLH
tHIGH
tLOW
tR_CL
tR_CL1
tR_DA
tF_CL
tF_DA
tHD:STA
tSU:STA
tHD:DAT
tSU:DAT
tSU:STO
tSP

Parameter
SCLH clock frequency
SCLH clock “High” time
SCLH clock “Low” time
SCLH rise time
SCLH rise time after a repeated START
condition and after an acknowledge bit
SDAH rise time
SCLH fall time
SDAH fall time
Start Condition hold time
Start Condition setup time
SDAH hold time (vs. SCLH falling edge)
SDAH setup time (vs. SCLH rising edge)
Stop Condition setup time
Noise suppression pulse width
Min.
Parameter
SCLH clock frequency
SCLH clock “High” time
SCLH clock “Low” time
SCLH rise time
SCLH rise time after a repeated START
condition and after an acknowledge bit
SDAH rise time
SCLH fall time
SDAH fall time
Start Condition hold time
Start Condition setup time
SDAH hold time (vs. SCLH falling edge)
SDAH setup time (vs. SCLH rising edge)
Stop Condition setup time
Noise suppression pulse width
Min.
Typ.
Max.
2.5
110
220
10
40
Unit
MHz
ns
ns
ns
10
80
ns
10
160
160
0
10
160
80
40
80
ns
ns
ns
ns
ns
ns
ns
ns
ns
10
Cb≤400pF
fSCLH≤1.7MHz
Symbol
fSCLH
tHIGH
tLOW
tR_CL
tR_CL1
tR_DA
tF_CL
tF_DA
tHD:STA
tSU:STA
tHD:DAT
tSU:DAT
tSU:STO
tSP
MS1526-E-01
Typ.
Max.
1.7
120
320
20
80
Unit
MHz
ns
ns
ns
20
160
ns
20
160
160
0
10
160
160
80
160
ns
ns
ns
ns
ns
ns
ns
ns
ns
10
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[AK09911]
[I2C bus interface timing of Hs-mode]
1/fSCLH
VIH1
SCLH
VIL1
START
Tf_D
START
STOP
Tr_D
VIH1
SDAH
VIL1
tSU;STA
tHD;DAT
tSU;STO
tSU;DAT
tHD;STA
VIH1
SCLH
VIL1
tf_CL
tr_CL1
Tr_CL1
Tr_CL
tHIGH tLOW
tHIGH
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6. Function Explanation
6.1. Power States
When VDD and VID are turned on from Vdd=OFF (0V) and Vid=OFF (0V), all registers in AK09911 are initialized by
POR circuit and AK09911 transits to Power-down mode.
All the states in the table below can be set, although the transition from state 2 to state 3 and the transition from state 3 to
state 2 are prohibited.
Table 6.1. Power state
State
1
VDD
OFF (0V)
VID
OFF (0V)
2
OFF (0V)
1.65V to 3.6V
3
2.4V to 3.6V
OFF (0V)
4
2.4V to 3.6V
1.65V to Vdd
Power state
OFF (0V).
It doesn’t affect external interface.Digital
input pins other than SCL and SDA pin
should be fixed to “L”(0V).
OFF (0V)
It doesn’t affect external interface.
OFF(0V)
It doesn’t affect external interface. Digital
input pins other than SCL and SDA pin
should be fixed to “L”(0V).
ON
6.2. Reset Functions
When the power state is ON, always keep Vid≤Vdd.
Power-on reset (POR) works until Vdd reaches to the operation effective voltage (about 1.1V: reference value for design)
on power-on sequence. After POR is deactivated, all registers are initialized and transits to Power-down mode.
When Vdd=2.4 to 3.6V, POR circuit and VID monitor circuit are active. When Vid=0V, AK09911 is in reset status and it
consumes the current of reset state (IDD4).
AK09911 has four types of reset;
(1) Power on reset (POR)
When Vdd rise is detected, POR circuit operates, and AK09911 is reset.
(2) VID monitor
When VID is turned OFF, AK09911 is reset.
(3) Reset pin (RSTN)
AK09911 is reset by Reset pin. When Reset pin is not used, connect to VID.
(4) Soft reset
AK09911 is reset by setting SRST bit. When AK09911 is reset, all registers are initialized and AK09911 transits to
Power-down mode.
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[AK09911]
6.3. Operation Mode
AK09911 has following nine operation modes:
(1) Power-down mode
(2) Single measurement mode
(3) Continuous measurement mode 1
(4) Continuous measurement mode 2
(5) Continuous measurement mode 3
(6) Continuous measurement mode 4
(7) Self-test mode
(8) Fuse ROM access mode
By setting CNTL2 register MODE[4:0] bits, the operation set for each mode is started.
A transition from one mode to another is shown below.
MODE[4:0]=“00001”
Power-down
MODE[4:0]=“00000”
mode
Transits automatically
MODE[4:0]=“00010”
MODE[4:0]=“00000”
MODE[4:0]=“00100”
MODE[4:0]=“00000”
MODE[4:0]=“00110”
MODE[4:0]=“00000”
MODE[4:0]=“01000”
MODE[4:0]=“00000”
MODE[4:0]=“10000”
MODE[4:0]=“00000”
Single measurement mode
Sensor is measured for one time and data is output.
Transits to Power-down mode automatically after
measurement ended.
Continuous measurement mode 1
Sensor is measured periodically in 10Hz.
Transits to Power-down mode by writing MODE[4:0]
= “00000”.
Continuous measurement mode 2
Sensor is measured periodically in 20Hz.
Transits to Power-down mode by writing
MODE[4:0]=“00000”.
Continuous measurement mode 3
Sensor is measured periodically in 50Hz.
Transits to Power-down mode by writing
MODE[4:0]=“00000”.
Continuous measurement mode 4
Sensor is measured periodically in 100Hz.
Transits to Power-down mode by writing
MODE[4:0]=“00000”.
Self-test mode
Sensor is self-tested and the result is output. Transits
to Power-down mode automatically.
Transits automatically
MODE[4:0]=“11111”
MODE[4:0]=“00000”
Fuse ROM access mode
Turn on the needed to read out Fuse ROM. Transits
to Power-down mode by writing
MODE[4:0]=“00000”.
Figure 6.1. Operation mode
When power is turned ON, AK09911 is in Power-down mode. When a specified value is set to MODE[4:0], AK09911
transits to the specified mode and starts operation. When user wants to change operation mode, transit to Power-down mode
first and then transit to other modes. After Power-down mode is set, at least 100 µs (Twat) is needed before setting another
mode
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[AK09911]
6.4. Description of Each Operation Mode
6.4.1. Power-down Mode
Power to almost all internal circuits is turned off. All registers are accessible in Power-down mode. Data stored in
read/write registers are remained. They can be reset by soft reset.
6.4.2. Single Measurement Mode
When Single measurement mode (MODE[4:0]=“00001”) is set, magnetic sensor measurement is started. After magnetic
sensor measurement and signal processing is finished, measurement magnetic data is stored to measurement data registers
(HXL to HZH), then AK09911 transits to Power-down mode automatically. On transition to Power-down mode,
MODE[4:0] turns to “00000”. At the same time, DRDY bit in ST1 register turnes to “1”. This is called “Data Ready”.
When any of measurement data register (HXL to TMPS) or ST2 register is read, DRDY bit turnes to “0”. It remains “1” on
transition from Power-down mode to another mode. (Figure 6.2. )
When sensor is measuring (Measurement period), measurement data registers (HXL to TMPS) keep the previous data.
Therefore, it is possible to read out data even in measurement period. Data read out in measurement period are previous
data.(Figure 6.3. )
Operation Mode:
Power-down
Single measuremnet
(1)
(2)
(3)
Measurement period
Measurement Data Register
Last Data
Measurement Data (1)
Data(2)
Data(3)
DRDY
Data read
Data(1)
Register Write
MODE[4:0]="00001"
Data(3)
MODE[4:0]="00001" MODE[4:0]="00001"
Figure 6.2. Single measurement mode when data is read out of measurement period
Operation Mode:
Power-down
Single measuremnet
(1)
(2)
(3)
Measurement period
Measurement Data Register
Last Data
Measurement Data (1)
Data(3)
DRDY
Data read
Register Write
Data(1)
MODE[4:0]="00001"
MODE[4:0]="00001" MODE[4:0]="00001"
Figure 6.3. Single measurement mode when data read started during measurement period
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[AK09911]
6.4.3. Continuous Measurement Mode 1, 2, 3 and 4
When Continuous measurement mode 1 (MODE[4:0]=“00010”), 2 (MODE[4:0]=“00100”), 3 (MODE[4:0]=“00110”) or 4
(MODE[4:0]=“01000”) is set, magnetic sensor measurement is started periodically at 10 Hz, 20 Hz, 50 Hz or 100 Hz
respectively. After magnetic sensor measurement and signal processing is finished, measurement magnetic data is stored to
measurement data registers (HXL to HZH) and all circuits except for the minimum circuit required for counting cycle
length are turned off (PD). When the next measurement timing comes, AK09911 wakes up automatically from PD and
starts measurement again.
Continuous measurement mode ends when Power-down mode (MODE[4:0]=“00000”) is set. It repeats measurement until
Power-down mode is set.
When Continuous measurement mode 1 (MODE[4:0]=“00010”), 2 (MODE[4:0]=“00100”), 3 (MODE[4:0]=“00110”) or 4
(MODE[4:0]=“01000”) is set again while AK09911 is already in Continuous measurement mode, a new measurement starts.
ST1, ST2 and measurement data registers (HXL to TMPS) will not be initialized by this.
(N-1)th
PD
Nth
Measurement
(N+1)th
Measurement
PD
PD
10Hz,20Hz,50Hz or 100Hz
Figure 6.4. Continuous measurement mode
6.4.3.2. Data Ready
When measurement data is stored and ready to be read, DRDY bit in ST1 register turnes to “1”. This is called “Data Ready”.
When measurement is performed correctly, AK09911 becomes Data Ready on transition to PD after measurement.
6.4.3.3. Normal Read Sequence
(1) Check Data Ready or not by polling DRDY bit of ST1 register
 DRDY: Shows Data Ready or not. Not when “0”, Data Ready when “1”.
 DOR: Shows if any data has been skipped before the current data or not. There are no skipped data when “0”,
there are skipped data when “1”.
(2) Read measurement data
When any of measurement data register (HXL to TMPS) or ST2 register is read, AK09911 judges that data reading
is started. When data reading is started, DRDY bit and DOR bit turnes to “0”.
(3) Read ST2 register (required)
 HOFL: Shows if magnetic sensor is overflowed or not. “0” means not overflowed, “1” means overflowed.
When ST2 register is read, AK09911 judges that data reading is finished. Stored measurement data is protected
during data reading and data is not updated. By reading ST2 register, this protection is released. It is required to read
ST2 register after data reading.
(N-1)th
PD
Nth
Measurement
(N+1)th
Measurement
PD
Measurement Data Register
(N-1)th
Nth
PD
(N+1)th
DRDY
Data read
ST1 Data(N)
ST2
ST1 Data(N+1)
ST2
Figure 6.5. Normal read sequence
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[AK09911]
6.4.3.4. Data Read Start during Measurement
When sensor is measuring (Measurement period), measurement data registers (HXL to TMPS) keep the previous data.
Therefore, it is possible to read out data even in measurement period. If data is started to be read during measurement period,
previous data is read.
(N-1)th
PD
Nth
Measurement
(N+1)th
Measurement
PD
PD
Measurement Data Register
(N-1)th
Nth
DRDY
Data read
ST1 Data(N)
ST2
ST1 Data(N)
ST2
Figure 6.6. Data read start during measurement
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[AK09911]
6.4.3.5. Data Skip
When Nth data was not read before (N+1)th measurement ends, Data Ready remains until data is read. In this case, a set of
measurement data is skipped so that DOR bit turnes to “1”.
When data reading started after Nth measurement ended and did not finish reading before (N+1)th measurement ended, Nth
measurement data is protected to keep correct data. In this case, a set of measurement data is skipped and not stored so that
DOR bit turnes to “1”.
In both case, DOR bit turnes to “0” at the next start of data reading.
(N-1)th
PD
Nth
Measurement
(N+1)th
Measurement
PD
Measurement Data Register
(N-1)th
Nth
PD
(N+1)th
DRDY
DOR
Data read
ST1 Data(N+1)
ST2
Figure 6.7. Data Skip: When data is not read
(N-1)th
PD
Nth
Measurement
(N+1)th
PD
(N+2)th
PD
Measurement
PD
Measurement
Measurement Data Register
(N-1)th
Nth
(N+2)th
Data register is protected
because data is being read
Not data ready
because data is not updated
DRDY
(N+1)th data is skipped
DOR
Data read
ST1 DataN
ST2
ST1 Data(N+2)
Figure 6.8. Data Skip: When data read has not been finished before the next measurement end
6.4.3.6. End Operation
Set Power-down mode (MODE[4:0]=“00000”) to end Continuous measurement mode.
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6.4.3.7. Magnetic Sensor Overflow
AK09911 has the limitation for measurement range that the sum of absolute values of each axis should be smaller than 4912
μT.
|X|+|Y|+|Z| < 4912 μT
When the magnetic field exceeded this limitation, data stored at measurement data are not correct. This is called Magnetic
Sensor Overflow.
When magnetic sensor overlow occurs, HOFL bit turns to “1”. When the next measurement starts, it returns to “0”.
6.4.4. Self-test Mode
Self-test mode is used to check if the magnetic sensor is working normally.
When Self-test mode (MODE[4:0]=“10000”) is set, magnetic field is generated by the internal magnetic source and
magnetic sensor is measured. Measurement data is stored to measurement data registers (HXL to HZH), then AK09911
transits to Power-down mode automatically.
Data read sequence and functions of read-only registers in Self-test mode is the same as Single measurement mode.
6.4.4.1. Self-test Sequence
(1) Set Power-down mode. (MODE[4:0]=“00000”)
(2) Set Self-test mode. (MODE[4:0]=“10000”)
(3) Check Data Ready or not by polling DRDY bit of ST1 register
When Data Ready, proceed to the next step.
(4) Read measurement data (HXL to HZH)
6.4.4.2. Self-test Judgment
When measurement data read by the above sequence is in the range of following table after sensitivity adjustment (refer to
8.3.11), AK09911 is working normally.
Criteria
HX[15:0]
-30 ≤ HX ≤ +30
HY[15:0]
-30 ≤ HY ≤ +30
HZ[15:0]
-400 ≤ HZ ≤ -50
6.4.5. Fuse ROM Access Mode
Fuse ROM access mode is used to read Fuse ROM data. Sensitivity adjustment data for each axis is stored in fuse ROM.
Set Fuse ROM Access mode (MODE[4:0]=“11111”) before reading Fuse ROM data. When Fuse ROM Access mode is set,
circuits required for reading fuse ROM are turned on.
After reading fuse ROM data, set Power-down mode (MODE[4:0]=“00000”) before the transition to another mode.
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[AK09911]
7. Serial Interface
The I2C bus interface of AK09911 supports the Standard mode (100 kHz max.), the Fast mode (400 kHz max.) and the
High-speed mode (Hs-mode, 2.5 MHz max.).
7.1. Data Transfer
To access AK09911 on the bus, generate a start condition first.
Next, transmit a one-byte slave address including a device address. At this time, AK09911 compares the slave address with
its own address. If these addresses match, AK09911 generates an acknowledgement, and then executes READ or WRITE
instruction. At the end of instruction execution, generate a stop condition.
7.1.1. Change of Data
A change of data on the SDA line must be made during “Low” period of the clock on the SCL line. When the clock signal
on the SCL line is “High”, the state of the SDA line must be stable. (Data on the SDA line can be changed only when the
clock signal on the SCL line is “Low”.)
During the SCL line is “High”, the state of data on the SDA line is changed only when a start condition or a stop condition
is generated.
SCL
SDA
DATA LINE
STABLE :
DATA VALID
CHANGE
OF DATA
ALLOWED
Figure 7.1. Data Change
7.1.2. Start/Stop Condition
If the SDA line is driven to “Low” from “High” when the SCL line is “High”, a start condition is generated. Every
instruction starts with a start condition.
If the SDA line is driven to “High” from “Low” when the SCL line is “High”, a stop condition is generated. Every
instruction stops with a stop condition.
SCL
SDA
START CONDITION
STOP CONDITION
Figure 7.2. Start and Stop Condition
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7.1.3. Acknowledge
The IC that is transmitting data releases the SDA line (in the “High” state) after sending 1-byte data.
The IC that receives the data drives the SDA line to “Low” on the next clock pulse. This operation is referred as
acknowledge. With this operation, whether data has been transferred successfully can be checked.
AK09911 generates an acknowledge after reception of a start condition and slave address.
When a WRITE instruction is executed, AK09911 generates an acknowledge after every byte is received.
When a READ instruction is executed, AK09911 generates an acknowledge then transfers the data stored at the specified
address. Next, AK09911 releases the SDA line then monitors the SDA line. If a master IC generates an acknowledge
instead of a stop condition, AK09911 transmits the 8bit data stored at the next address. If no acknowledge is generated,
AK09911 stops data transmission.
Clock pulse
for acknowledge
SCL FROM
MASTER
1
9
8
DATA
OUTPUT BY
TRANSMITTER
not acknowledge
DATA
OUTPUT BY
RECEIVER
START
CONDITION
acknowledge
Figure 7.3. Generation of Acknowledge
7.1.4. Slave Address
The slave address of AK09911 can be selected from the following list by setting CAD pin. When CAD pin is fixed to VSS,
the corresponding slave address bit is “0“. When CAD pin is fixed to VDD, the corresponding slave address bit is “1“.
Table 7.1. Slave Address and CAD pin
CAD
0
1
Slave Address
0CH
0DH
MSB
0
LSB
0
0
1
1
0
CAD
R/W
Figure 7.4. Slave Address
The first byte including a slave address is transmitted after a start condition, and an IC to be accessed is selected from the
ICs on the bus according to the slave address.
When a slave address is transferred, the IC whose device address matches the transferred slave address generates an
acknowledge then executes an instruction. The 8th bit (least significant bit) of the first byte is a R/W bit.
When the R/W bit is set to “1“, READ instruction is executed. When the R/W bit is set to “0“, WRITE instruction is
executed.
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7.2. WRITE Instruction
When the R/W bit is set to “0”, AK09911 performs write operation.
In write operation, AK09911 generates an acknowledge after receiving a start condition and the first byte (slave address)
then receives the second byte. The second byte is used to specify the address of an internal control register and is based on
the MSB-first configuration.
MSB
A7
LSB
A6
A5
A4
A3
A2
A1
A0
Figure 7.5. Register Address
After receiving the second byte (register address), AK09911 generates an acknowledge then receives the third byte.
The third and the following bytes represent control data. Control data consists of 8 bits and is based on the MSB-first
configuration. AK09911 generates an acknowledge after every byte is received. Data transfer always stops with a stop
condition generated by the master.
MSB
D7
LSB
D6
D5
D4
D3
D2
D1
D0
Figure 7.6. Control Data
AK09911 can write multiple bytes of data at a time.
After reception of the third byte (control data), AK09911 generates an acknowledge then receives the next data. If
additional data is received instead of a stop condition after receiving one byte of data, the address counter inside the LSI
chip is automatically incremented and the data is written at the next address.
The address is incremented from 00H to 18H, from 30H to 32H, or from 60H to 62H. When the address is 00H to 18H, the
address is incremented 00H  01H  02H  03H  10H  11H ...  18H,and the address goes back to 00H after
18H. When the address is 30H to 32H, the address goes back to 30H after 32H. When the address is 60H to 62H, the
address goes back to 60H after 62H.
Actual data is written only to Read/Write registers (refer to Table 8.2. ).
S
T
A
R
T
SDA
S
S
T
O
P
R/W="0"
Slave
Address
Register
Address(n)
A
C
K
Data(n)
A
C
K
Data(n+1)
A
C
K
Data(n+x)
A
C
K
A
C
K
P
A
C
K
Figure 7.7. WRITE Instruction
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[AK09911]
7.3. READ Instruction
When the R/W bit is set to “1”, AK09911 performs read operation.
If a master IC generates an acknowledge instead of a stop condition after AK09911 transfers the data at a specified address,
the data at the next address can be read.
Address can be 00H to 18H, 30H to 32H, and 60H to 62H. When the address is 00H to 18H, the address is incremented 00H
 01H  02H  03H  10H  11H ...  18H,and the address goes back to 00H after 18H. When the address is 30H
to 32H, the address goes back to 30H after 32H. When the address is 60H to 62H, the address goes back to 60H after 62H.
AK09911 supports one byte read and multiple byte read.
7.3.1. One Byte READ
AK09911 has an address counter inside the LSI chip. In current address read operation, the data at an address specified by
this counter is read.
The internal address counter holds the next address of the most recently accessed address.
For example, if the address most recently accessed (for READ instruction) is address “n”, and a current address read
operation is attempted, the data at address “n+1” is read.
In one byte read operation, AK09911 generates an acknowledge after receiving a slave address for the READ instruction
(R/W bit=“1”). Next, AK09911 transfers the data specified by the internal address counter starting with the next clock pulse,
then increments the internal counter by one. If the master IC generates a stop condition instead of an acknowledge after
AK09911 transmits one byte of data, the read operation stops.
S
T
A
R
T
SDA
S
S
T
O
P
R/W="1"
Slave
Address
Data(n)
A
C
K
Data(n+1)
A
C
K
Data(n+2)
A
C
K
Data(n+x)
A
C
K
P
A
C
K
Figure 7.8. One Byte READ
7.3.2. Multiple Byte READ
By multiple byte read operation, data at an arbitrary address can be read.
The multiple byte read operation requires to execute WRITE instruction as dummy before a slave address for the READ
instruction (R/W bit=“1”) is transmitted. In random read operation, a start condition is first generated then a slave address
for the WRITE instruction (R/W bit=“0”) and a read address are transmitted sequentially.
After AK09911 generates an acknowledge in response to this address transmission, a start condition and a slave address for
the READ instruction (R/W bit=“1”) are generated again. AK09911 generates an acknowledge in response to this slave
address transmission. Next, AK09911 transfers the data at the specified address then increments the internal address counter
by one. If the master IC generates a stop condition instead of an acknowledge after data is transferred, the read operation
stops.
S
T
A
R
T
SDA
S
S
T
A
R
T
R/W="0"
Slave
Address
Register
Address(n)
A
C
K
S
A
C
K
S
T
O
P
R/W="1"
Slave
Address
Data(n)
A
C
K
Data(n+1)
A
C
K
Data(n+x)
A
C
K
P
A
C
K
Figure 7.9. Multiple Byte READ
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7.4. High-speed Mode (Hs-mode)
AK09911 supports the Hs-mode.
Hs-mode can only commence after the following conditions (all of which are in Fast/Standard-mode):
 START condition (S)
 8-bit master code (00001XXX)
 not-acknowledge bit (Ā)
The diagram below shows data flow of the Hs-mode.
After start condition, feed master code 00001XXX for transfer to the Hs-mode. And then AK09911 feeds back
not-acknowledge bit and swich over to circuit for the Hs-mode between times t1 and tH. AK09911 can communicate at the
Hs-mode from next START condition. At time tFS, AK09911 switchs its internal circuit from the Hs-mode to the First
mode with the STOP condition (P). This transfer completes in the bus free time (tBUF).
Figure 7.10. Data transfer format in Hs-mode
Figure 7.11. Hs-mode transfer
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[AK09911]
8. Registers
8.1. Description of Registers
AK09911 has registers of 20 addresses as indicated in Every address consists of 8 bits data. Data is transferred to or
received from the external CPU via the serial interface described previously.
Table 8.1. Register Table
00H
READ/
WRITE
READ
Campany ID
Bit
width
8
WIA2
01H
READ
Device ID
8
INFO1
02H
READ
Information 1
8
INFO2
03H
READ
Information 2
8
ST1
10H
READ
Status 1
8
Data status
HXL
11H
READ
Measurement Magnetic Data
8
X-axis data
HXH
12H
READ
8
Name
Address
WIA1
Description
Remarks
HYL
13H
READ
8
HYH
14H
READ
8
Y-axis data
HZL
15H
READ
8
HZH
16H
READ
8
TMPS
17H
READ
Dummy Register
8
Dummy
ST2
18H
READ
Status 2
8
Data status
CNTL1
30H
Dummy Register
8
Dummy
CNTL2
31H
Control 2
8
Control settings
CNTL3
32H
Control 3
8
Control settings
TS1
33H
Test
8
DO NOT ACCESS
ASAX
60H
READ/
WRITE
READ/
WRITE
READ/
WRITE
READ/
WRITE
READ
X-axis sensitivity adjustment value
8
Fuse ROM
ASAY
61H
READ
Y-axis sensitivity adjustment value
8
Fuse ROM
ASAZ
62H
READ
Z-axis sensitivity adjustment value
8
Fuse ROM
Z-axis data
Addresses 00H to 18H, 30H to 32H and 60H to 62H are compliant with automatic increment function of serial interface
respectively. Values of addresses 60H to 62H can be read only in Fuse ROM access mode. In other modes, read data is not
correct. When the address is in 00H to 18H, the address is incremented 00H  01H  02H  03H  10H  11H ... 
18H, and the address goes back to 00H after 18H. When the address is in 30H to 32H, the address goes back to 30H after
32H. When the address is in 60H to 62H, the address goes back to 60H after 62H.
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[AK09911]
8.2. Register Map
Table 8.2. Register Map
Addr.
Register
name
D7
D6
D5
D4
Read-only register
1
0
0
0
0
0
INFO16 INFO15 INFO14
INFO26 INFO25 INFO24
0
0
0
HX6
HX5
HX4
HX14
HX13
HX12
HY6
HY5
HY4
HY14
HY13
HY12
HZ6
HZ5
HZ4
HZ14
HZ13
HZ12
0
0
0
0
0
0
Read/Wright register
0
0
0
D3
D2
D1
D0
1
0
INFO13
INFO23
0
HX3
HX11
HY3
HY11
HZ3
HZ11
0
HOFL
0
1
INFO12
INFO22
0
HX2
HX10
HY2
HY10
HZ2
HZ10
0
0
0
0
INFO11
INFO21
DOR
HX1
HX9
HY1
HY9
HZ1
HZ9
0
0
0
1
INFO10
INFO20
DRDY
HX0
HX8
HY0
HY8
HZ0
HZ8
0
0
00H
01H
02H
03H
10H
11H
12H
13H
14H
15H
16H
17H
18H
WIA1
WIA2
INFO1
INFO2
ST1
HXL
HXH
HYL
HYH
HZL
HZH
TMPS
ST2
0
0
INFO17
INFO27
HSM
HX7
HX15
HY7
HY15
HZ7
HZ15
0
0
30H
CNTL1
0
0
0
0
0
31H
CNTL2
0
0
0
MODE4
MODE3
MODE2
MODE1
MODE0
32H
CNTL3
0
0
0
0
0
0
0
SRST
33H
TS1
-
-
-
-
-
-
-
-
60H
61H
62H
ASAX
ASAY
ASAZ
Read-only register
COEFX7 COEFX6 COEFX5 COEFX4 COEFX3 COEFX2 COEFX1 COEFX0
COEFY7 COEFY6 COEFY5 COEFY4 COEFY3 COEFY2 COEFY1 COEFY0
COEFZ7 COEFZ6 COEFZ5 COEFZ4 COEFZ3 COEFZ2 COEFZ1 COEFZ0
When VDD is turned ON, POR function works and all registers of AK09911 are initialized regardless of VID status. To
write data to or to read data from register, VID must be ON.
TS1 is test registers for shipment test. Do not use these registers.
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8.3. Detailed of Description of Register
8.3.1. WIA: Who I Am
Addr
00H
01H
Register
name
WIA1
WIA2
D7
0
0
D6
1
0
D5
D4
Read-only register
0
0
0
0
D3
D2
D1
D0
1
0
0
1
0
0
0
1
D2
D1
D0
WIA1[7:0]: Company ID of AKM. It is described in one byte and fixed value.
48H: fixed
WIA2[7:0]: Device ID of AK09911. It is described in one byte and fixed value.
05H: fixed
8.3.2. INFO: Information
Addr
Register
name
02H
03H
INFO1
INFO2
D7
D6
D5
D4
D3
Read-only register
INFO17 INFO16 INFO15 INFO14 INFO13 INFO12 INFO11 INFO10
INFO27 INFO26 INFO25 INFO24 INFO23 INFO22 INFO21 INFO20
INFO1[7:0]/INFO2[7:0]: Device information of AKM.
8.3.3. ST1: Status 1
Addr
10H
Register
name
ST1
Reset
D7
D6
HSM
0
0
0
D5
D4
Read-only register
0
0
0
0
D3
D2
D1
D0
0
0
0
0
DOR
0
DRDY
0
DRDY: Data Ready
“0“: Normal
“1“: Data is ready
DRDY bit turns to “1” when data is ready in Single measurement mode, Continuous measurement mode 1, 2, 3, 4 or
Self-test mode. It returns to “0” when any one of ST2 register or measurement data register (HXL to TMPS) is read.
DOR: Data Overrun
“0”: Normal
“1”: Data overrun
DOR bit turns to “1” when data has been skipped in Continuous measurement mode 1, 2, 3, 4. It returns to “0” when any
one of ST2 register or measurement data register (HXL to TMPS) is read.
HSM: I2C Hs-mode
“0”: Standard/Fast mode
“1”: Hs-mode
HSM bit turns to “1” when I2C bus interface is changed from Standard or Fast mode to High-speed mode (Hs-mode).
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8.3.4. HXL to HZH: Measurement data
Addr
11H
12H
13H
14H
15H
16H
Register
name
HXL
HXH
HYL
HYH
HZL
HZH
Reset
D7
D6
HX7
HX15
HY7
HY15
HZ7
HZ15
0
HX6
HX14
HY6
HY14
HZ6
HZ14
0
D5
D4
Read-only register
HX5
HX4
HX13
HX12
HY5
HY4
HY13
HY12
HZ5
HZ4
HZ13
HZ12
0
0
D3
D2
D1
D0
HX3
HX11
HY3
HY11
HZ3
HZ11
0
HX2
HX10
HY2
HY10
HZ2
HZ10
0
HX1
HX9
HY1
HY9
HZ1
HZ9
0
HX0
HX8
HY0
HY8
HZ0
HZ8
0
Measurement data of magnetic sensor X-axis/Y-axis/Z-axis
HXL[7:0]: X-axis measurement data lower 8-bit
HXH[15:8]: X-axis measurement data higher 8-bit
HYL[7:0]: Y-axis measurement data lower 8-bit
HYH[15:8]: Y-axis measurement data higher 8-bit
HZL[7:0]: Z-axis measurement data lower 8-bit
HZH[15:8]: Z-axis measurement data higher 8-bit
Measurement data is stored in two’s complement and Little Endian format. Measurement range of each axis is -8190 to
8190.
Table 8.3. Measurement magnetic data format
Measurement data (each axis) [15:0]
Two’s complement
Hex
Decimal
0001 1111 1111 1110
1FFE
8190
|
|
|
0000 0000 0000 0001
0001
1
0000 0000 0000 0000
0000
0
1111 1111 1111 1111
FFFF
-1
|
|
|
1110 0000 0000 0010
E002
-8190
Magnetic flux
density [µＴ]
4912(max.)
|
0.6
0
-0.6
|
-4912(min.)
8.3.5. TMPS: Dummy Register
Addr
17H
Register
name
TMPS
Reset
D7
0
0
D6
0
0
D5
D4
Read-only register
0
0
0
0
D3
D2
D1
D0
0
0
0
0
0
0
0
0
Dummy register.
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8.3.6. ST2: Status 2
Addr
18H
Register
name
ST2
Reset
D7
D6
0
0
0
0
D5
D4
Read-only register
0
0
0
0
D3
D2
D1
D0
HOFL
0
0
0
0
0
0
0
HOFL: Magnetic sensor overflow
“0”: Normal
“1”: Magnetic sensor overflow occurred
In Single measurement mode, Continuous measurement mode 1, 2, 3, 4, and Self-test mode, magnetic sensor may overflow
even though measurement data regiseter is not saturated. In this case, measurement data is not correct and HOFL bit turns to
“1”. When next measurement stars, it returns to “0”. Refer to 6.4.3.6 for detailed information.
ST2 register has a role as data reading end register, also. When any of measurement data register (HXL to TMPS) is read in
Continuous measurement mode 1, 2, 3, 4, it means data reading start and taken as data reading until ST2 register is read.
Therefore, when any of measurement data is read, be sure to read ST2 register at the end.
8.3.7. CNTL1: Dummy Register
Addr
30H
Register
name
CNTL1
Reset
D7
D6
0
0
0
0
D7
D6
D5
D4
Read/Write register
0
0
0
0
D3
D2
D1
D0
0
0
0
0
0
0
0
0
D3
D2
D1
D0
Dummy register.
8.3.8. CNTL2: Control 2
Addr
31H
Register
name
CNTL2
Reset
0
0
0
0
D5
D4
Read/Write register
0
MODE4 MODE3
0
0
0
MODE2
0
MODE1 MODE0
0
0
MODE[4:0]: Operation mode setting
“00000”: Power-down mode
“00001”: Single measurement mode
“00010”: Continuous measurement mode 1
“00100”: Continuous measurement mode 2
“00110”: Continuous measurement mode 3
“01000”: Continuous measurement mode 4
“10000”: Self-test mode
“11111”: Fuse ROM access mode
Other code settings are prohibited
.
When each mode is set, AK09911 transits to the set mode. Refer to 6.3 for detailed information.
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8.3.9. CNTL3: Control 3
Register
name
Addr
32H
CNTL3
Reset
D7
D6
0
0
0
0
D5
D4
Read/Write register
0
0
0
0
D3
D2
D1
D0
0
0
0
0
0
0
SRST
0
SRST: Soft reset
“0”: Normal
“1”: Reset
When “1” is set, all registers are initialized. After reset, SRST bit turns to “0” automatically.
8.3.10. TS1: Test
Register
name
Addr
33H
TS1
Reset
D7
0
D6
0
D5
D4
Read/Write register
0
0
D3
D2
D1
D0
0
0
0
0
D3
D2
D1
D0
TS1 register is AKM internal test register. Do not use this register.
8.3.11. ASAX, ASAY, ASAZ: Sensitivity Adjustment Values
Addr
60H
61H
62H
Register
name
ASAX
ASAY
ASAZ
Reset
D7
D6
D5
D4
Read-only register
COEFX7 COEFX6 COEFX5 COEFX4 COEFX3 COEFX2 COEFX1 COEFX0
COEFY7 COEFY6 COEFY5 COEFY4 COEFY3 COEFY2 COEFY1 COEFY0
COEFZ7 COEFZ6 COEFZ5 COEFZ4 COEFZ3 COEFZ2 COEFZ1 COEFZ0
-
Sensitivity adjustment data for each axis is stored to fuse ROM on shipment.
ASAX[7:0]: Magnetic sensor X-axis sensitivity adjustment value
ASAY[7:0]: Magnetic sensor Y-axis sensitivity adjustment value
ASAZ[7:0]: Magnetic sensor Z-axis sensitivity adjustment value

How to adjust sensitivity
The sensitivity adjustment is done by the equation below,
 ASA 
Hadj = H × 
+ 1
 128

where H is the measurement data read out from the measurement data register, ASA is the sensitivity adjustment
value, and Hadj is the adjusted measurement data.
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9. Example of Recommended External Connection
Host CPU
VID
POWER 1.65V to Vdd
VDD
POWER 2.4V to 3.6V
Power for I/F
GPIO
0.1µF
SDA
2
I C I/F
RSTN
VID
C
AK09911C
SCL
0.1µF
VSS
(Top view)
TST
3
CAD
2
VDD
B
A
1
Slave address select
CAD
VSS
VDD
address
0 0 0 1 1 0 0 R/W
0 0 0 1 1 0 1 R/W
Pins of dot circle should be kept non-connected.
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10. Package
10.1. Marking


Date code:
X1X2X3X4X5
 X1 = ID
 X2 = Year code
 X3X4 = Week code
 X5 = Lot
Product name: 9911
X1X2X3X4X5
9911
<Top view>
10.2. Pin Assignment
C
B
A
3
SDA
SCL
TST
2
RSTN
CAD
1
VID
VSS
VDD
<Top view>
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10.3. Outline Dimensions
[mm]
1.19±0.03
3
2
0.8
1
1
2
3
0.4
0.8
1.19±0.03
C
B
A
0.4
0.24±0.03
0.40
0.57 max.
0.13
0.05 C
C
10.4. Recommended Foot Print Pattern
[mm]
3
2
1
C
0.4
B
A
0.4
0.23
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11. Relationsip between the Magnetic Field and Output Code
The measurement data increases as the magnetic flux density increases in the arrow directions.
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[AK09911]
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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