AK8975.pdf 데이터시트 (총 30 페이지) - 파일 다운로드 AK8975 데이타시트 다운로드

No Preview Available !

[AK8975/C]
AK8975/AK8975C
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
13 bit data out for each 3 axis magnetic components
- Sensitivity: 0.3 µT / LSB typ.
Serial interface
- I2C bus interface.
Standard mode and Fast mode compliant with Philips I2C specification Ver.2.1
- 4-wire SPI
Operation mode:
Power-down mode, Single Measurement mode, Self test mode and Fuse access mode.
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 built-in 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:
10 µA max.
Measurement:
- Average power consumption at 8 Hz repetition rate: 350 µA typ.
Package:
AK8975 16-pin QFN package:
AK8975C 14-pin WL-CSP (BGA):
4.0 mm × 4.0 mm × 0.75 mm
2.0 mm × 2.0 mm × 0.6 mm
MS1187-E-02
-1-
2010/05

No Preview Available !

[AK8975/C]
2. Overview
AK8975/C is 3-axis electronic compass IC with high sensitive Hall sensor technology.
Small package of AK8975/C 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.
AK8975/C 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:
13 bit (0.3 µT / LSB)
Measurement range:
±1200 µT
Average power consumption at 8Hz repetition rate: 350 µA typ.
(3) Digital serial interface
- I2C bus interface to control AK8975/C 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-wire SPI is also supported. A dedicated power supply for SPI can work in low-voltage apply as low as
1.65V.
(4) DRDY pin and register inform 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.
MS1187-E-02
-2-
2010/05

No Preview Available !

[AK8975/C]
3. Table of Contents
1. Features ....................................................................................................................................1
2. Overview ...................................................................................................................................2
3. Table of Contents ......................................................................................................................3
4. Circuit Configuration ..................................................................................................................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 .....................................................................................8
5.3.4. 4-wire SPI ...................................................................................................................9
5.3.5. I2C Bus Interface .......................................................................................................10
6. Functional Explanation ............................................................................................................ 11
6.1. Power States .................................................................................................................... 11
6.2. Reset Functions ............................................................................................................... 11
6.3. Operation Modes..............................................................................................................12
6.4. Description of Each Operation Mode................................................................................13
6.4.1. Power-down Mode ....................................................................................................13
6.4.2. Single Measurement Mode .......................................................................................13
6.4.2.1. Data Ready ........................................................................................................13
6.4.2.2. Data Error ..........................................................................................................14
6.4.2.3. Magnetic Sensor Overflow .................................................................................14
6.4.3. Self-test Mode ...........................................................................................................15
6.4.4. Fuse ROM Access Mode ..........................................................................................15
7. Serial Interface ........................................................................................................................16
7.1. 4-wire SPI.........................................................................................................................16
7.1.1. Writing Data ..............................................................................................................16
7.1.2. Reading Data ............................................................................................................17
7.2. I2C Bus Interface ..............................................................................................................18
7.2.1. Data Transfer ............................................................................................................18
7.2.1.1. Change of Data..................................................................................................18
7.2.1.2. Start/Stop Condition ...........................................................................................18
7.2.1.3. Acknowledge......................................................................................................19
7.2.1.4. Slave Address ....................................................................................................19
7.2.2. WRITE Instruction .....................................................................................................20
7.2.3. READ Instruction.......................................................................................................21
7.2.3.1. One Byte READ .................................................................................................21
7.2.3.2. Multiple Byte READ ...........................................................................................21
8. Registers .................................................................................................................................22
8.1. Description of Registers ...................................................................................................22
8.2. Register Map....................................................................................................................23
8.3. Detailed Description of Registers .....................................................................................24
8.3.1. WIA: Device ID..........................................................................................................24
8.3.2. INFO: Information......................................................................................................24
8.3.3. ST1: Status 1.............................................................................................................24
8.3.4. HXL to HZH: Measurement Data...............................................................................25
8.3.5. ST2: Status 2.............................................................................................................26
8.3.6. CNTL: Control ...........................................................................................................26
8.3.7. RSV: Reserved .........................................................................................................27
8.3.8. ASTC: Self Test Control ............................................................................................27
8.3.9. TS1, TS2: Test 1, 2 ...................................................................................................27
8.3.10. I2CDIS: I2C Disable...................................................................................................27
8.3.11. ASAX, ASAY, ASAZ: Sensitivity Adjustment values...................................................28
MS1187-E-02
-3-
2010/05

No Preview Available !

[AK8975/C]
9. Example of Recommended External Connection ....................................................................29
9.1. I2C Bus Interface ..............................................................................................................29
9.2. 4-wire SPI.........................................................................................................................30
10. Package ..................................................................................................................................31
10.1. Marking ............................................................................................................................31
10.2. Pin Assignment ................................................................................................................31
10.3. Outline Dimensions ..........................................................................................................32
10.4. Recommended Foot Print Pattern ....................................................................................33
11. Relationship between the Magnetic Field and Output Code....................................................34
MS1187-E-02
-4-
2010/05

No Preview Available !

[AK8975/C]
4.1. Block Diagram
4. Circuit Configuration
3-axis
Hall
sen sor
MUX
Chopper
SW
Pre-
AMP
Integrator ADC
Magnetic source
HE -Driv e
Voltage
Reference
OSC1
Timin g
Control
CAD0
CAD1 TST1 TST2 RSV
TST6
POR
VSS VDD VID
Interface,
Logic
& Register
FUSE ROM
SCL/SK
SDA/SI
CSB
SO
DRDY
4.2. Block Function
Block
Function
3-axis Hall sensor Monolithic Hall elements.
MUX
Multiplexer for selecting Hall elements.
Chopper SW
Performs chopping.
HE-Drive
Magnetic sensor drive circuit for constant-current driving of sensor
Pre-AMP
Variable-gain differential amplifier used to amplify the magnetic sensor signal.
Integrator & ADC Integrates and amplifies pre-AMP output and performs analog-to-digital
conversion.
OSC1
Generates an operating clock for sensor measurement.
6.144MHz(typ.)
POR
Power On Reset circuit. Generates reset signal on rising edge of VDD.
Interface Logic
Exchanges data with an external CPU.
DRDY pin indicates sensor measurement end and data is ready to be read.
I2C bus interface using two pins, namely, SCL and SDA. Standard mode and Fast
mode are supported. The low-voltage specification can be supported by applying
1.65V to the VID pin.
4-wire SPI is also supported by SK, SI, SO and CSB pins.
4-wire SPI works in VID pin voltage down to 1.65V, too.
Timing Control
Generates a timing signal required for internal operation from a clock generated
by the OSC1.
Magnetic Source Generates magnetic field for self test of magnetic sensor.
FUSE ROM
Fuse for adjustment
MS1187-E-02
-5-
2010/05