oki tri-axis accelerometer module ml8952 · short-range development plan of oki...

CONFIDENTIAL

OKI TRI-AXIS ACCELEROMETER MODULEML8952

OKI Electric Industry Co., Ltd.WP Business Development WP Business division

Silicon Manufacturing Company

CONFIDENTIAL

CONTENTS

What’s tri-axis accelerometer ?

Typical applications

Outline of ML8952

Specification

Roadmap of OKI motion sensor

Demonstration of free fall detection

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It can detect….

ACCELERATION

SHOCK

VIBRATION3D MOTION

What’s tri-axis accelerometer?What’s tri-axis accelerometer?

TILT

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PERSONAL MOBILE

COMUNICATION DEVICES

Electric Compass Correction

Safeguard Protection of HDD (freefall detection)

Pedometer

3D Mouse Control

Car Navigation System

Emerging Potential forMEMS-based Tri-Axis Accelerometers

SECURITY

Anti-theft alarms- motorcycles - ATM (automatic teller machines) etc.

Burglary alarms

Typical ApplicationsTypical Applications

Fault Vibration Detector

Seismograph (Earthquake sensor)

Tilt Angle Compensationfor Projector

Electric Level

INDUSTRIALGAMES

Display Controller

Input Controller

Robot Posture Controller

(Cell phones, PDA, Watch)

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Application to electronic compass correctionApplication to electronic compass correction• Introduction of a mobile phone with GPS and electronic compass in 2002

The mobile phone had to remainat an even level with the ground *

Tri-axis accelerometer (tilt sensor) clears this problem

tri-axis accelerometer

tri-axis accelerometer signal

processing unitsignal

processing unit

earth’s magneticfield sensor

earth’s magneticfield sensor

Electronic CompassElectronic CompassCell phones , PDAOKI

Drawing up a road map !

GPS +

* Existing earth’s magnetic field sensors have compass error depending on an operating tilt-angle.

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Package Feature of ML8952 (Commercial Device)

Package Feature of ML8952 (Commercial Device)

LCC 18 pin packageSize: 6.3 mm(W) x 6.2 mm(D) x 1.2 mm(H) (world's thinnest)Pb Free & Halogen Free

14

13

123

4

5

6

7

8

9 11 12

15

16

17

18

10

6.2

6.3

ML8

952

2.0 x 2.0

1.90.8

0.8

R 0.15

1 x 0.45

1.55

1.5 x 0.45

TOP VIEW BOTTOM VIEW

SIDE VIEW

1.0

(mm)

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Feature ML8950 (Type A) (Tech. Eval. Purpose) ML8952 (Type B’) (Commercial Device)

Package Size 5.0 x 5.0 x 1.4 (mm) 14-pin LCC 6.3 x 6.2x 1.2 (mm) 18-pin LCC

Calibration No internal EEPROM for calibration data Calibration data is stored on internal EEPROM (factory stored)

SPI and I2C SPI

3-wire serial I/F (SIOCLK, SIODT, SIOST)

4-wire serial I/F (SIOCLK, SIDT, SODT, SIOST)

CLK Frequency CLK Frequency

~ 1.53 MHz (SPI), ~ 400KHz (I2C) ~12MHz (EEPROM: ~ 1MHz)

<Automatic Compensation> <Automatic Compensation>

No automatic temperature compensationAutomatic temperature compensation for its sensitivity and offset value using a built-in temperature sensor and the calibration data.

<Automatic Measurement > <Automatic Measurement >

Only measurement controlled by external MPUIncluding automatic measurement mode, controlled by an internal CLK. When a G variation is detected, a interrupt signal is triggered to host CPU.

<Automatic Interrupt> <Automatic Interrupt>

No interrupt functionIncluding a programmable level-interrupt that can be triggered by freefall detection (0G), shock detection (G over threshold setting) or by sensing motion depending on the G variation.

<Time Averaging> <Time Averaging>

No time-averaging function

Including time-averaging function that can minimize the output data spread by time-averaging measured data per unit time. The given measurement times are 4, 16 and 64, which can be chosen suitable for customers applications.

Logic Control Circuit

CPU Interface

Feature Differences between Type A and Type B’Feature Differences between Type A and Type B’

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☆Our accelerometer is useful for HDD damage protection systems・No gravity (static acceleration) detection （~ 0G）→ offers retraction of a HDD’s head to safe position by detecting no

gravity during falling・ Collision/vibration (dynamic acceleration) detection→ features fast response time upon collision （＜10msec）. Possible to

stop the access safely resulting in avoidance of structive damage.

Automatic detection mode issues Automatic detection mode issues automatic interrupt signal to HOST CPUautomatic interrupt signal to HOST CPUwhen set value is exceeded.when set value is exceeded.

落下時の加速度イメージ

0.0

1.0

2.0

経過時間

加速度（絶対値表示）

1G+α

-α

Steady state

Falling

After collision

0G+α

Sample waveform

Elapsed time

Acc

eler

atio

n (A

bsol

ute

valu

e)An example of applications

- HDD damage protection -An example of applications

- HDD damage protection -

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Static Output Characteristic of AccelerometerStatic Output Characteristic of Accelerometer

-200.0-150.0-100.0-50.00.0050.0

100.0150.0200.0

0 30 60 90 120 150 180 210 240 270 300 330 360Angle [deg]

Out

put [

bit]

Vy

< y-axis Rotation >Y

X

Z

Vz

Vx

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Structure of OKI’s Piezoresistivity AccelerometerStructure of OKI’s Piezoresistivity Accelerometer

X

Z

Y

AL Pad

SiO2 (BOX)SOI

Piezoresistance

Beam

Overview

Cross-section

SOI Waf.Si Sub.Weight

AccelerationOn Weight

Strain/tensionOn Beams

ResistanceChange

Change in resistance can be read as proportional to acceleration

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Rx2Rx1

Rx3Rx4

Rz1Rz2

Ry1

Ry3Ry4

Ry2 Rz3 Rz4

Bridge CircuitsRx1- Rx4

X direction Ry1 - Ry4

Y direction Rz1 - Rz4

Z direction

<Top View >

X(Y) axis acceleration Z axis acceleration

R1 R2

R3R4E

R1 R2

R3 R4E Vout

Resistance Change due to mechanical Stress

stretch strainresistance increase(+)

compression strainresistance decrease(-)

+ +

Fx(y)

R4R3+

Fz

Vout

R2R1R3 R4R1 R2beam beam beambeam

Basic Principle of Acceleration DetectionBasic Principle of Acceleration Detection

- - - - <Piezoresistive Effect>+

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AdvantagesAdvantagesWorld’s Thinnest Package --- LCC:1.2 mm TypicalEasy of Use--- Serial Digital Interface (SPI)--- Application Development Tool available (I/F board and Software)Software)Environment --- Available in Pb Free & Halogen FreeA lot of functions -- Logic control supports several operational modes

Type

5 x 5.6 x2.0

4.8 x 4.8 x 1.3

6.3 x 6.2 x 1.2

PKG Size(mm3)

0~ +60AnalogHokuriku Electric Ind.

Hitachi Metal -25~ +75 +/- 2gAnalog

-20~ +70+/- 2gDigitalOKI

Operating Temp.

Range( C)

Detection RangeInterfacecompetitors

7 x 7 x 1.8 -40~ +85DigitalST Micron

+/- 2g

+/- 2gcapacitance

PiezoresistPiezoresist..

PiezoresistPiezoresist..

PiezoresistPiezoresist..

5.0x 5.0 x2.0 0~ +70AnalogADI

5.0 x 5.0 x 2.0 -40~ +70MEMSIC

+/- 2g

+/- 2g

capacitancecapacitance

Thermal Analog

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ML8952 SpecificationML8952 Specification

serial Digital I/F (SPI)Interface

mm6.3 (W) x 6.2 (D) x 1.2 (H)PKG Size (Typical)10.0 (Max)

2.5 (Max)

0.5 (Average)10

mA @RTCurrent consumption

Stand-by Current

(Acceleration)

Supply Voltage

CHARACTERISTICS SPECIFICATION (typ.) UNIT

+2.5 to +3.3 (analog)+1.8 to +3.3 (Digital) V

Detection range +/- 2 g

Detection Resolution (Angle)

mg/bit

/bit

Non linearity +/- 5 %FS

%FSOff-axial sensitivity +/- 10Response frequency DC~100 Hz

Shock survivability > 5000 g

Operating Temp. Range -20 to +70( -4 to + 158 ) C (deg F)

uA @70 C

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Short-range Development Plan of OKI AccelerometerShort-range Development Plan of OKI Accelerometer

2005 2006Target

ES: Jun. 2005~ MP: Dec. 2005~

Fall Model

ES: Winter 2005~ MP: Summer 2006~

Type B (1.0mm-thick-PKG)- 6.3 x 6.2 x 1.0mm- Built-in EEPROM- 4-wire-SPI- Freefall detection/ wake-up function- Time-averaging function

Type-C (Small size version)- 4.8 x 4.8 x 1.2mm- Built-in EEPROM- 4-wire-SPI- Freefall detection/wake-up function- Time-averaging function

Spring Model

ES: Winter 2006~ MP: Summer 2007~

Spring ModelFall Model

- Major target: Mobile-phone -- Major target: Mobile-phone -

** To be Sequentially Developed for the futureTo be Sequentially Developed for the future

year 2007

Type B’ (1.2mm-thick PKG, High shock-resistance version)- 6.3 x 6.2 x 1.2mm

Type-D (Electronic Compass)- 3D Earth Magnetic Field Sensor+ 3D Accelerometer- 6.3 x 6.2 x 1.2mm(preliminary)

ES: Summer 2006~ MP: Winter 2006~

ES: Apr. 2005~ MP: Sep. 2005~

Type-E (5D Motion Sensor)- 2D Gyro sensor +3D Accelerometer

<ML8951>

<ML8952>

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Roadmap of OKI Motion Sensor (Long-range)Roadmap of OKI Motion Sensor (Long-range)

Teak

FERAM 3-axis angular velocity sensor3-axis angular velocity sensor

3-axis accelerometer3-axis accelerometer

6-axis motion sensor6-axis motion sensor

- DSC , Video camera: correction of distortion with hand motion

- Toy robot

- DSC , Video camera: correction of distortion with hand motion

- Toy robot

- Detection of a bicycle turn over- Game controller- Electronic compass correction

- Detection of a bicycle turn over- Game controller- Electronic compass correction

- High-end posture controller

(robot, vehicle)Flash

EEPROM

U8

ARM

Sensor Correction, Signal Processing Technology

AMP, LPF

- More highly functional MEMS sensors plus ICs -- More highly functional MEMS sensors plus ICs -

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Oki Provides Total Silicon Solutions for Customer’s NeedsLong Term Partnership with Customers

Oki Provides Total Silicon Solutions for Customer’s NeedsLong Term Partnership with Customers

THANK YOU