Sensors for Low Level Signal Acquisition - VE2013
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Transcript of Sensors for Low Level Signal Acquisition - VE2013
Sensors for Low Level Signal Acquisition Advanced Techniques of Higher Performance Signal Processing
David Kress – Director of Technical Marketing Nitzan Gadish – MEMS Applications Engineer
Legal Disclaimer
Notice of proprietary information, Disclaimers and Exclusions Of Warranties The ADI Presentation is the property of ADI. All copyright, trademark, and other intellectual property and proprietary rights in the ADI Presentation and in the software, text, graphics, design elements, audio and all other materials originated or used by ADI herein (the "ADI Information") are reserved to ADI and its licensors. The ADI Information may not be reproduced, published, adapted, modified, displayed, distributed or sold in any manner, in any form or media, without the prior written permission of ADI. THE ADI INFORMATION AND THE ADI PRESENTATION ARE PROVIDED "AS IS". WHILE ADI INTENDS THE ADI INFORMATION AND THE ADI PRESENTATION TO BE ACCURATE, NO WARRANTIES OF ANY KIND ARE MADE WITH RESPECT TO THE ADI PRESENTATION AND THE ADI INFORMATION, INCLUDING WITHOUT LIMITATION ANY WARRANTIES OF ACCURACY OR COMPLETENESS. TYPOGRAPHICAL ERRORS AND OTHER INACCURACIES OR MISTAKES ARE POSSIBLE. ADI DOES NOT WARRANT THAT THE ADI INFORMATION AND THE ADI PRESENTATION WILL MEET YOUR REQUIREMENTS, WILL BE ACCURATE, OR WILL BE UNINTERRUPTED OR ERROR FREE. ADI EXPRESSLY EXCLUDES AND DISCLAIMS ALL EXPRESS AND IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT OF ANY THIRD PARTY INTELLECTUAL PROPERTY RIGHTS. ADI SHALL NOT BE RESPONSIBLE FOR ANY DAMAGE OR LOSS OF ANY KIND ARISING OUT OF OR RELATED TO YOUR USE OF THE ADI INFORMATION AND THE ADI PRESENTATION, INCLUDING WITHOUT LIMITATION DATA LOSS OR CORRUPTION, COMPUTER VIRUSES, ERRORS, OMISSIONS, INTERRUPTIONS, DEFECTS OR OTHER FAILURES, REGARDLESS OF WHETHER SUCH LIABILITY IS BASED IN TORT, CONTRACT OR OTHERWISE. USE OF ANY THIRD-PARTY SOFTWARE REFERENCED WILL BE GOVERNED BY THE APPLICABLE LICENSE AGREEMENT, IF ANY, WITH SUCH THIRD PARTY.
2
Today’s Agenda
Sensors are the source
Sensor signals are typically low level and difficult
Signal conditioning is key to high performance
Silicon sensors are integrated with signal conditioning
Applications keep demanding higher accuracy
Motion sensors with moving silicon elements are driving systems in all market areas
Silicon microphone sensors with high sensitivity
3
Analog to Electronic Signal Processing
SENSOR (INPUT)
DIGITAL PROCESSOR AMP CONVERTER
ACTUATOR (OUTPUT)
AMP CONVERTER
6
Popular Sensors
Sensor Type Output
Thermocouple Voltage
Photodiode Current
Strain gauge Resistance
Microphone Capacitance
Touch button Charge output
Antenna RF -- Inductance
Acceleration Capacitance
7
Sensor Signal Conditioning
SENSOR AMP
Analog, electronic, but “dirty”
Analog, electronic, and “clean”
Amplify the signal to a noise-resistant level
Lower the source impedance
Linearize (sometimes but not always)
Filter
Protect
8
Designing Sensors in Silicon
Sensor signals are typically low level and subject to noise coupling on connections to amplifiers
Bring signal conditioning as close to sensor as possible Multichip hybrids Silicon sensor on same chip as amplifier/data converter
Environmental issues Extreme temperature or vibration Sensor needs to be small for sensitivity
Finding silicon property that responds to physical variable Capacitance, stress, temperature change
9
Silicon Sensors
Sensor Type Output
Temperature Voltage/current
Photodiode Current
Strain gauge Resistance
Microphone Capacitance
Rotation Capacitance
Antenna RF -- Inductance
Acceleration Capacitance
10
Historical sensors
5000BC Egypt, evidence for Weight measurement
Temperature Scales 1593 Galileo Galilei: Water Thermoscope Differential Temperature Sensing
1612 Santorio Santorio put scale on Thermoscope
Daniel Gabriel Fahrenheit 1714 (32F, 212F, 180 divisions) First Thermometer with Scale, mercury
Anders Celsius 1742 (0, 100C, 100 divisions) Lord Kelvin 1848 (0K, Centigrade divisions) William Johnson 1883 -- thermostat
11
Modern „Thermoscope“
Types of Temperature Sensors
12
THERMOCOUPLE RTD THERMISTOR SEMICONDUCTOR
Widest Range:
–184ºC to +2300ºC
Range:
–200ºC to +850ºC
Range:
0ºC to +100ºC
Range:
–55ºC to +150ºC
High Accuracy and
Repeatability
Fair Linearity Poor Linearity Linearity: 1ºC
Accuracy: 1ºC
Needs Cold Junction
Compensation
Requires
Excitation
Requires
Excitation
Requires Excitation
Low-Voltage Output Low Cost High Sensitivity 10mV/K, 20mV/K,
or 1µA/K TypicalOutput
Basic Relationships for Semiconductor Temperature Sensors
IC IC
VBE VN
∆VBE VBE VNkTq
N= − = ln( )
VBEkTq
ICIS
=
ln
=
S
CN IN
Iq
kTV×
ln
INDEPENDENT OF IC, IS
ONE TRANSISTOR N TRANSISTORS
13
Classic Band Gap Temperature Sensor
"BROKAW CELL" R R
+ I2 ≅ I1
Q2 NA
Q1 A
R2
R1
VN VBE (Q1)
VBANDGAP = 1.205V
+VIN
VPTAT = 2 R1 R2
kT q ln(N)
∆VBE VBE VNkTq
N= − = ln( )
14
Analog Temperature Sensors
16
Product Accuracy (Max)
Max Accuracy Range
Operating Temp Range
Supply Range
Max Current Interface Package
AD590 ±0.5°C ±1.0°C
25°C −25°C to +105°C
−55°C to +150°C
4 V to 30 V 298 µA Current out TO-52, 2-lead FP, SOIC, Die
AD592 ±0.5°C ±1.0°C
25°C −55°C to +150°C
−25°C to +105°C
4 V to 30 V 298 µA
Current out TO-92
TMP35 ±2.0°C 0°C to 85°C −25°C to +100°C
−55°C to +150°C
2.7 V to 5.5 V 50 µA
Voltage out TO-92, SOT23, SOIC
TMP36 ±3.0°C −40°C to +125°C
−55°C to +150°C
2.7 V to 5.5 V 50 µA
Voltage out TO-92, SOT23, SOIC
AD221100
±2.0°C −50°C to +150°C
−55°C to +150°C
4 V to 6.5 V 650 µA
Voltage out TO-92, SOIC, Die
AD22103
±2.5°C 0°C to +100°C
0°C to +100°C
2.7 V to 3.6 V 600 µA
Voltage out TO-92, SOIC
Digital Temperature Sensors Comprehensive Portfolio of Accuracy Options
17
Product Accuracy (Max) Max Accuracy Range Interface Package
ADT7420/ADT7320 ±0.2°C ±0.25°C
−10°C to +85°C −20°C to +105°C I2C/SPI LFCSP
ADT7410/ADT7310 ±0.5°C −40°C to +105°C I2C/SPI SOIC
ADT75 ±1°C (B grade) ±2°C (A grade)
0°C to 85°C −25°C to +100°C I2C MSOP, SOIC
ADT7301 ±1°C
0°C to 70°C SPI SOT23, MSOP
TMP05/TMP06 ±1°C
0°C to 70°C PWM SC70, SOT23
AD7414/ADT7415 ±1.5°C
−40°C to +70°C I2C SOT23, MSOP
ADT7302 ±2°C 0°C to 70°C SPI SOT23, MSOP
TMP03/TMP04 ±4°C
−20°C to +100°C
PWM TO-92, SOIC, TSSOP
High Accuracy Temperature Sensing Applications Scientific, medical and aerospace Instrumentation Medical equipment Laser beam positioners
Test and measurement Calorimeters Automatic test equipment Mass spectrometry Thermo cyclers/DNA analyzers Infrared imaging Data acquisition/analyzers Flow meters
Process control Instruments/controllers
Critical asset monitoring Food and pharmaceutical
Environmental monitoring 18
18
Digital IC RTD Thermistor
Ease of Use
Sensor selection and sourcing
Reliable supply and specifications
Need to determine reliable suppliers (specifications std.)
Need to determine reliable suppliers and specifications
Extra signal processing Additional sourcing, selection, design, evaluation, testing, manufacturing
No
Precision ADC (≥16 bits) Current source Amp (optional) Precision resistor Filter caps
ADC (resolution is app specific) Current source Amp (optional) Precision resistor Filter caps
Linearization No Yes Yes
Calibration No Yes Yes Resistance concerns No Yes Yes Self heating concerns No Yes Yes
Reliability Contact resistance No Susceptible Susceptible
Batch variation No Susceptible Susceptible Transmission noise No Susceptible Susceptible
Performance Accuracy range Industrial Range Wide range Commercial range
Stability High High Low
Repeatability High High Low
High Performance Temperature Measurement Sensor Comparison d
19
Thermocouple
Very low level (µV/ºC)
Nonlinear
Difficult to handle
Wires need insulation
Susceptible to noise
Fragile
21
Common Thermocouples
22
Junction Materials Typical Useful Range (°C)
Nominal Sensitivity (µV/°C)
ANSI Designation
Platinum (6%)/Rhodium- Platinum (30%)/Rhodium
38 to 1800 7.7 B
Tungsten (5%)/Rhenium- Tungsten (26%)/Rhenium
0 to 2300 16 C
Chromel-Constantan 0 to 982 76 E
Iron-Constantan 0 to 760 55 J
Chromel-Alumel −184 to +1260 39 K
Platinum (13%)/Rhodium- Platinum
0 to 1593 11.7 R
Platinum (10%)/Rhodium- Platinum
0 to 1538 10.4 S
Copper-Constantan −184 to +400 45 T
Thermocouple Seebeck Coefficient vs. Temperature
-250 0 250 500 750 1000 1250 1500 17500
10
20
30
40
50
60
70
SEEB
ECK
CO
EFFI
CIE
NT
-µV/
°C
TEMPERATURE (°C)
TYPE J
TYPE K
TYPE S
-250 0 250 500 750 1000 1250 1500 17500
10
20
30
40
50
60
70
SEEB
ECK
CO
EFFI
CIE
NT
-µV/
°C
TEMPERATURE (°C)
TYPE J
TYPE K
TYPE S
23
Thermocouple Basics
24
T1
METAL A
METAL B
THERMOELECTRIC EMF
R METAL A METAL A
R = TOTAL CIRCUIT RESISTANCE I = (V1 – V2) / R
V1 T1 V2 T2
V1 – V2
METAL B
METAL A METAL A
V1
V1
T1
T1
T2
T2
V2
V2
V METAL A METAL A
COPPER COPPER
METAL B METAL B
T3 T4
V = V1 – V2, IF T3 = T4
A. THERMOELECTRIC VOLTAGE
B. THERMOCOUPLE
C. THERMOCOUPLE MEASUREMENT
D. THERMOCOUPLE MEASUREMENT
I
V1 T1
METAL A
METAL B EMF
R METAL A METAL A
R = TOTAL CIRCUIT RESISTANCE I = (V1 – V2) / R
V1 T1 V2 T2
V1 – V2
METAL B
METAL A METAL A
V1
V1
T1
T1
T2
T2
V2
V2
V METAL A
COPPER COPPER
METAL B METAL B
T3 T4
V = V1 – V2, IF T3 = T4
A. THERMOELECTRIC VOLTAGE
B. THERMOCOUPLE
C. THERMOCOUPLE MEASUREMENT
D. THERMOCOUPLE MEASUREMENT
I
V1
Using a Temperature Sensor for Cold-Junction Compensations
TEMPERATURECOMPENSATION
CIRCUIT
TEMPSENSOR
T2V(T2)T1 V(T1)
V(OUT)V(COMP)
SAMETEMP
METAL A
METAL B
METAL A
COPPERCOPPER
ISOTHERMAL BLOCKV(COMP) = f(T2)
V(OUT) = V(T1) – V(T2) + V(COMP)
IF V(COMP) = V(T2) – V(0°C), THEN
V(OUT) = V(T1) – V(0°C)
TEMPERATURECOMPENSATION
CIRCUIT
TEMPSENSOR
T2V(T2)T1 V(T1)
V(OUT)V(COMP)
SAMETEMP
METAL A
METAL B
METAL A
COPPERCOPPER
ISOTHERMAL BLOCKV(COMP) = f(T2)
V(OUT) = V(T1) – V(T2) + V(COMP)
IF V(COMP) = V(T2) – V(0°C), THEN
V(OUT) = V(T1) – V(0°C)
25
Thermocouple Amplifiers AD849x Product Features and Description Factory trimmed for Type J and K thermocouples Calibrated for high accuracy
Cold Junction Compensation (CJC) IC temps of 25°C and 60°C
Output voltage of 5 mV/°C Active pull-down Rail-to-Rail output swing
Wide power supply range +2.7 V to ±15 V Low power < 1 mW typical Package–space saving MSOP-8, lead-free Low cost < $1 in volume Can measure negative temperatures in single-supply operation
26
Part Number Thermocouple Type
Optimized Temp Range
Measurement Temp Range
Initial Accuracy
AD8494 J 0 to 50°C Full J type range ±1°C and ±3°C
AD8495 K 0 to 50°C Full K type range ±1°C and ±3°C
AD8496 J 25°C to 100°C Full J type range ±1.5°C and ±3°C
AD8497 K 25°C to 100°C Full K type range ±1.5°C and ±3°C
Demo Using a Temperature Sensor for Cold-Junction Compensations–CN0271 Figure 1. K-type thermocouple measurement system with integrated
cold junction compensation (simplified schematic: all connections not shown)
27
AD8495
OUT
SENSE
REF –VS
+VS+VS
–VS
INP
INN
0.1µF 10µF
+5V
+2.5V
COLDJUNCTION
COMPENSATION
THERMO-COUPLE
1MΩ 100Ω49.9kΩ0.01µF
0.01µF
1.0µF100Ω
0.1µF 0.1µF10µF
+5V +2.5V
IN-AMP
+OUT
–OUT
AD8476
10kΩ
10kΩ
10kΩ
10kΩ
100Ω 0.01µF
0.01µF
1.0µF100Ω SERIAL
INTERFACE
INTERNALCLOCK
16-BITADC
GND
REFIN
AD7790
DIGITALPGABUF
VDDVDD
GND
+5VADR441+5V
+2.5VVIN VOUTGND
1059
8-00
1
High Accuracy Applications Thermocouple Cold-Junction Compensation Benefits High accuracy High accuracy, low drift cold junction measurement using ADT7X20
Fast throughput Parallel measurement of hot and cold junction gives fastest throughput
Flexibility Software-based solution
enabling use of multiple thermocouple types
Easy implementation Fully integrated digital
temp measurement solution
Low cost No costly multipoint
cold-junction calibration required
28
High Accuracy Applications CJC using ADT7320
29
ADT7320 for cold- junction temperature measurement
Thermocouple isothermal connector
ADT7320 mounted on Flex PCB
Σ-Δ ADC
Temperature Measurement RTD Sensor
Key application benefits 3-wire RTD 2 matched excitation currents 40 nV RMS at gain = 64 Ratiometric configuration 50 Hz and 60 Hz rejection (−75 dB)
30
RL1
RL2
RL3
RTD
GND VDD
AD7793
SERIALINTERFACE
ANDCONTROL
LOGIC
INTERNALCLOCK
CLK
SIGMADELTAADC
IOUT1
MUXIN-AMP
REFIN(+) REFIN(-)BANDGAPREFERENCE
GND
SPI SERIALINTERFACE
IOVDD
VDD
GND
IOUT2
REFIN
AIN1
RREFEXCITATIONCURRENTS
High Impedance Sensors
Photodiodes
Piezoelectric sensors Accelerometers Hydrophones
Humidity monitors
pH monitors
Chemical sensors
Smoke detectors
Charge coupled devices
Contact image sensors for imaging
31
Photodiode Equivalent Circuit
33
PHOTO CURRENT
IDEAL DIODE
INCIDENT LIGHT
RSH(T) 100kΩ - 100GΩ
CJ
Note: RSH halves every 10°C temperature rise
Photodiode Modes Of Operation
Photovoltaic Zero bias No “dark" current Linear Low noise (Johnson) Precision applications
Photoconductive Reverse bias Has “dark" current Nonlinear Higher noise (Johnson + shot) High speed applications
34
–
+
–VBIAS
–
+
Short Circuit Current vs. Light Intensity for Photodiode (Photovoltaic Mode)
35
Environment Illumination (fc) Short Circuit Current
Direct sunlight 1000 30 µA Overcast day 100 3 µA
Twilight 1 0.03 µA Full moonlit night 0.1 3000 pA
Clear night/no moon 0.001 30 pA
Current-to-Voltage Converter (Simplified)
36
ISC = 30pA (0.001 fc)
+
_
R = 1000MΩ
VOUT = 30mV
SENSITIVITY: 1mV / pA
Complete Photodiode Sensing Application CN0272 Figure 1. Photodiode preamp system with dark current
compensation (simplified schematic: all connections and decoupling not shown)
41
AVDD
CF
RF
RF
0.1µF0.1µF
3.3pF
VBIAS–5V
+1.8V
+0.9V
22pF
AD8065
SFH 2701
AD9629-20
VIN–
VIN+VCM
INP
INN
VOCM
+2.5V+OUT
–OUT
AD8475
1kΩ
2.5kΩ
24.9kΩ
24.9kΩ2.5kΩ
1kΩ
33Ω
33Ω
+5V
–5V
+5V
–5V
TP3
TP2
ADR441+5V
+2.5VVIN VOUTGND
GND
TP1
1059
9-00
1
FastFET Opamp Ib = 1pA BW = 145MHz Vn = 7nV/rtHz Cn = 0.6fA/rtHz
Sensor Resistances Used in Bridge Circuits Span a Wide Dynamic Range
42
Strain gages 120Ω, 350 Ω, 3500 Ω
Weigh scale load cells 350 Ω to 3500 Ω
Pressure sensors 350 Ω to 3500 Ω
Relative humidity 100 kΩ to 10 mΩ
Resistance temperature devices (RTDs) 100 Ω, 1000 Ω
Thermistors 100 Ω to 10 mΩ
For more information and demonstration of bridge sensors, attend the Instrumentation – Sensing 2 – session.
Position and Motion Sensors
Linear position: linear variable differential transformers (LVDT)
Hall effect sensors Proximity detectors Linear output (magnetic field strength)
Rotational position: Optical rotational encoders Synchros and resolvers Inductosyn® sensors (linear and rotational position) Motor control applications
Acceleration and tilt: accelerometers
Gyroscopes
Microphones
43
44
MEMS Sensors are Everywhere
Health and Fitness Products
Smartphones
Automotive Safety and Infotainment
Precision Agriculture
Avionics and Navigation
Fleet Management
Asset Tracking
ADI’s Motion Signal Processing ™ Enables… Motion Sensing
47
Fleet management
Alarm systems
Motion control and orientation of industrial robots
Precision agriculture
51
ADI’s Motion Signal Processing ™ Enables… Shock & Vibration Sensing
Power tool safety: Shock detection
Contact sports & industrial machinery: impact detection
White goods: vibration monitoring Predictive maintenance:
Vibration monitoring
53
ADI’s Motion Signal Processing ™ Enables… Rotation Sensing
Platform/antenna stabilization: Industrial, maritime, avionics, communications
Digital camera OIS Automotive Rollover
Detection
55
ADI’s Motion Signal Processing ™ Enables… Complex Motion Sensing
Platform Stabilization Guidance and trajectory: Mil/Aero
Detection of Motion in Free Space
Precision agriculture
MEMS at ADI: In the beginning…
Concept began in ~1986 Market: airbag sensors
1989 Demonstrated first working MEMS accelerometer
1991 First product samples
ADXL50: ADI’s First MEMS Device
A little history…
The first airbags used ball-in-tube sensors.
Concept began in ~1986 Market: airbag sensors
65
How Do MEMS Accelerometers Work?
Single axis accelerometer in silicon has the same components Left / Right (X-axis)
X Left Right M a s s
Proof Mass Suspension Spring
Suspension Spring
Motion
(ca. 1992-1995)
How Do iMEMS Accelerometers Work?
Single axis accelerometer in silicon has the same components Left/right (x-axis)
66
(ca. 1992-1995)
How Do iMEMS Accelerometers Work?
All moving parts are suspended above the substrate Sacrificial layer removed from below moving parts during fabrication
67
(ca. 1992-1995)
68
How Do MEMS Accelerometers Work?
Measurement of deflection is done with variable differential capacitor "finger sets"
(ca. 1992-1995)
Measuring the Position of the Proof Mass To help protect your privacy, PowerPoint has blocked automatic download of this picture.
X
Y
Differential capacitance used to pick off motion of mass C1 and C2 is the capacitance between the mass and a set of
fixed fingers Keep monitoring (C1 – C2) to determine if the mass has
moved in the X-axis
C1 C2
Measuring Tilt
A = G sinΦ
Acceleration due to tilt is the projection onto the sensitive axis of the gravity vector.
Φ Φ
G
Sensitive axis
G 17mg / ° tilt near level
m k
High Performance Accelerometers Industry’s Strongest and Most Complete Portfolio
Low-g
High-g
ADXL103
ADXL203
ADXL78
ADXL213
ADXL278
1
2
2
1
2 Two-Pole Bessel Filter
PWM Output
±1.7g
±1.7g
±1.7g
ADXL337 3
±3g
±35/50/70g
±35/50/70g
±70/250/500g
ADXL001 1
20-22KHz Bandwidth
ADIS16006 2
±5g 200 μg/√Hz rms SPI Temp Sensor
ADIS16003 2
±1.7g 110 μg/√Hz rms SPI Temp Sensor
0.1° accuracy Temperature Calibration Programmable/Alarms/Filtering
ADIS16209/3/1 2
±90, ±180g ADIS16227/3
3
±70g ADIS16204
2
Programmable Capture Buffers Peak Sample/Hold
±37/70g Function Specific
TILT / INCLINOMETER
Embedded FFT/Storage Programmable Alarm Bands MultiMode Operation
VIBRATION
ADXL326 ±16g
IMPACT
ADIS16240 3
±19g Programmable Triggers Event Capture Buffers
ADXL312 3
AECQ-100 Qualified
±1.5/3/6/12g
Up to 13bit resolution 30μA to 140μA power
3
IMPACT
iMEMs XL ANALOG
iMEMs XL DIGITAL
iSensor XL Digital
g
axes
axes
g
axes
g
ADXL206 2
±5g +175°C Operation
ADXL212 2
±5g
ADXL343 3
±2/4/8/16g ADXL344
3
±2/4/8/16g
ADXL345 3
±2/4/8/16g ADXL346
3
±2/4/8/16g
ADXL362 3
±2/4/8g
12bit resolution @ ±2g <2uA power consumption
ADXL377 3
±200g
ADXL350 3
Min/Max Temp Sensitivity
±1/2/4/8g
Focusing on High Performance with: • Industry Lowest Power Consumption • Industry Best Precision Over Lifetime • Industry Best Temperature Range • Industry Best Sensor/Signal Processing • Industry Best Integration … Performance Under All Conditions
Highlight Product: ADXL362: Industry’s Lowest Power MEMS Accel By far…
< 2 µA at 100 Hz in Measurement Mode 270 nA in Wake-Up Mode
Also helps save system power Enables Autonomous, Continuously Operational Motion-activated Switch Enhanced Activity/Inactivity Detection Deep FIFO
Gyro Building Blocks What does one need?
x
x
x
x
A Good XL
(We already know how to do that)
+
A gizmo that converts any rotation to a force
+
A coupling mechanism that transfers the force generated by the “gizmo” to the accelerometer
Gyro Building Blocks The Coriolis Effect: Converting rotation to force since 1835
MASS
ROTATION
OSCILLATION
CORIOLIS
FORCE
What is the Coriolis effect? In plain English… a moving mass, when rotated, imparts a force to resist change in direction of motion
Gyro Building Blocks
x
x
x
x
A Good XL
(We already know how to do that)
+ + A coupling mechanism that transfers the force generated by the “gizmo” to the accelerometer
Mass with velocity
Gyro Building Blocks
x
x
x
x
Coupling mechanism:
Cut a hole in the middle of XL and drop the “moving mass” inside
Mass with velocity
RESONATOR MOTION
Gyro Principle of Operation
79
ACCELEROMETER TETHER RESONATOR TETHER
ACCELEROMETER FRAME
RESONATOR
CO
RIO
LIS A
CC
ELE
RATIO
N
APPLIED ROTATION
ANCHOR
Problems with Single Mass Gyros
Single mass gyros generally cannot differentiate between rotation (which you want to measure) and vibration at the resonant frequency
83
Gyro Principle of Operation
84
Rotation Applied
-
+
ADXRS series design use two beams (masses) resonating in anti-phase (180° out of phase) Shock and vibration is common mode, so differential operation allows rejection
of many errors
Problems With Single Mass Gyros…
…are also problems with dual-mass gyros, just to a lesser extent.
That wasn’t good enough for us.
High Performance Gyro and IMU Industry’s Strongest and Most Complete Portfolio
Rate Grade
Tactical Grade
> 10 o/hr in-run Stability
< 10 o/hr in-run Stability
ADXRS45X
ADIS16265
ADXRS646
ADXRS642
0.015o/s/g 5mA
6 o/hr 16ppm/oC Sensitivity
ADIS1636X / 405/7
ADIS16305
6, 9, 10
4
ADIS16375 6
ADIS16334 6
ADIS16385 6
12o/hr; 0.13mg Stability 0.013o/s/g Continuous Bias Estimation
<8cm3 40ppm/oC
ADIS16135/3
6o/hr, Yaw
Quad-Core Designs Industry Leading Vibration
Immunity
ADXRS62x/ 652
Vertical Mount Package option
25ppm/oC Sensitivity
iMEMs Gyro ANALOG
iMEMs Gyro DIGITAL
iSensor Gyro Digital
IMU (DoF)-X
0.03o/s/g
ADIS16488
ADIS16448
in development
0.015o/s/g 1000o/sec range 40ppm/oC 8cm3
6 o/hr ; 0.1mg 0.009o/s/g
6 - 10
6 - 10
Up to 1200o/sec
ADIS16136 4 o/hr 0.18 ARW
goals
ADIS-NxGn ADXRS-NxGn
Highlight Product: ADXRS64x High Performance Gyroscope Series Quad differential sensor technology
Pin and package compatible to ADXRS62x family
Superb vibration rejection Sensitivity to Linear Acceleration as low as 0.015°/s/g Vibration Rectification as low as 0.0001°/s/g2
Various flavors: Bias stability as low as 12°/hour Rate noise density as low as 0.01°/s/√Hz Angular measurement range up to 50,000°/s Startup time as fast as 3 msec
Power consumption down to 3.5 mA
ADXRS64x Gyros Feature ADI’s Unique Quad Differential
Sensor Design
Microphone Technology Trends to MEMS Performance is unaffected by Pb-
free solder reflow temperature
Replaces high cost manual sorting and assembly with automated assembly
Higher SNR and superior matching
Higher mechanical shock resistance
Wider operating temperature range
Consumes less current
Superior performance part-to-part, overtemperature, and with vibration
92
MEMS
DIGITAL OUTPUT
MEMS
ANALOG OUTPUT
ECM
JFET
ADI Microphone Structure
Diaphragm and back plate electrodes form a capacitor
Sound pressure causes the diaphragm to vibrate and change the capacitance
Capacitance change is amplified and converted to analog or digital output
DIAPHRAGM
PERFORATED BACK PLATE
SPRING SUSPENSION SENSE GAP
Normal conversation: 60 dB (or 20 MPa) 0.55 nm (5.5 A)
Crying baby: 110 dB 170 nm (1700 A)
How Much Does ADI MEMS Microphone Diaphragm Move?
94
Why Use MEMS Microphones? Performance Density Electret mics performance degrades quickly in smaller packages
MEMS mics achieve new level of performance in the same volume as the smallest electrets!
95
70dB
55dB
Microphone Physical Volume (cubic millimeters)
10mm3 100 200 300 400 500 600 700
MEMS MICROPHONES
ELECTRET-BASED MICROPHONES
SNR
MEMS MICS SHIFTS THE SNR-TO-VOLUME SLOPE
UP DRAMATICALLY!
Why Use MEMS Microphones? Less Sensitivity Variation vs. Temperature ECM vs. ADMP441
96 Change (in dB) from original sensitivity
Top vs. Bottom Port: Performance Impact Bottom Port Provides Superior SNR & Frequency Response
97
All top-port microphones (MEMS and ECM) currently on the market have sharp peaks in their high-frequency response, making them unacceptable for wideband voice applications
All top-port microphones have low SNR (55…58 dB) There are no top-port microphones with high performance currently on the market
ADI Bottom-Port MEMS Microphone Competitor Top-Port MEMS Microphone
Industry’s Most Integrated MEMS Mic
ADMP441 integrates more of the signal chain than any other MEMS Mic!
Typical analog output mics (ADMP404) integrate an output amp Typical digital output mics (ADMP421) integrate an ADC and provide a single bit
output stream (known as “pulse density modulation” or PDM) – which still requires a filter and some signal processing and PDM codecs focus on mobile devices
ADMP441 provides full I2S output – the most common digital audio interface
ADMP441 ADMP421
ADMP404
Secondary Amplifier
Serializer I2S, etc.
Digital Signal Processor or
Microcontroller
Filter
ADI MEMS Microphone Portfolio High Performance MEMS Microphones
ADMP441 Full I2S-Output
Most integrated microphone
available!
ADMP421 61dB SNR
Pulse Density Modulated (PDM)
Output
Digital Output Higher Integration
Package
3.35x2.6x0.88 mm
4.72x3.76x1 mm
4x3x1 mm
Analog Output Flexibility in Signal Acquisition
ADMP405 62dB SNR
200 Hz to 15 kHz Flat Frequency Response
ADMP401 100 Hz to 15 kHz Flat Frequency Response
ADMP521 65dB SNR
Pulse Density Modulated (PDM)
Output
ADMP404 62dB SNR
100 Hz to 15 kHz Flat Frequency Response
ADMP504 65dB SNR
100 Hz to 15kHz Frequency Response
65dB SNR Family
62dB SNR Family
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What We Covered
Sensors are the source
Sensor signals are typically low-level and difficult
Signal conditioning is key to high performance
Silicon sensors are integrated with signal conditioning
Applications keep demanding higher accuracy
Motion sensors with moving silicon elements are driving systems in all market areas
100
Tweet it out! @ADI_News #ADIDC13
Design Resources Covered in this Session
Design Tools and Resources:
Ask technical questions and exchange ideas online in our EngineerZone ® Support Community Choose a technology area from the homepage: ez.analog.com
Access the Design Conference community here: www.analog.com/DC13community
101
Name Description URL
Photodiode Wizard Photodiode/amplifier design tool
Tweet it out! @ADI_News #ADIDC13
Selection Table of Products Covered Today
102
Part number Description AD590/592/TMP17 Two-terminal current-out temperature sensor AD849x Thermocouple amplifier w/cold junction compensation ADT7320/7420 0.25C accurate digital temperature sensors AD7793 24-bit ADC with RTD sensor driver ADA4638 Photodiode amplifier ADXL362 2µA high-resolution digital accelerometer ADXRS64X High performance gyroscope series ADMP404/504 High performance analog microphones ADMP441 Complete digital microphone w/ filter
Tweet it out! @ADI_News #ADIDC13
Visit the K-Type Thermocouple Measurement System with Integrated Cold-Junction Compensation (CN0271) in the Exhibition Room
This is a complete thermocouple measurement system with cold junction compensation for Type K. It includes a 16-bit Ʃ-∆ ADC, cold-junction amplifier, and low noise instrumentation amplifier to provide common-mode rejection for long lines.
103
Image of demo/board
This demo board is available for purchase: http://www.analog.com/DC13-hardware
Tweet it out! @ADI_News #ADIDC13
Visit the Tilt Measurement Demo in the Exhibition Room
104
Measure tilt using the ADXL203 dual axis accelerometer
This demo board is available for purchase: www.analog.com/DC13-hardware
SDP-S BOARD SOFTWARE OUTPUT DISPLAY EVAL-CN0189-SDPZ
Design Conference Schedule
105
Advanced Techniques of Higher Performance Signal Processing
Industry Reference Designs & Systems Applications
8:00 – 9:00 Registration
9:00-10:15 System Partitioning & Design
Signal Chain Designer: A new way to design online
High Speed Data Connectivity: More than Hardware
Process Control System
10:15-10:45 Break and Exhibit
10:45-12:00 Data Conversion: Hard Problems Made Easy
Amplify, Level Shift & Drive Precision Systems
Rapid Prototyping with Xilinx Solutions
Instrumentation: Liquid & Gas Sensing
12:00-1:30 Lunch and Exhibit
1:30-2:45 Frequency Synthesis and Clock Generation for High-Speed Systems
Sensors for Low level Signal Acquisition
Modeling with MATLAB® and Simulink®
Instrumentation: Test & Measurement Methods and Solutions
2:45-3:15 Break and Exhibit
3:15-4:30 High Speed & RF Design Considerations
Data & Power Isolation
Integrated Software Defined Radio
Motor Control
4:30-5:00 Exhibit and iPad drawing