Sensors for Low Level Signal Acquisition - VE2013

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Sensors are the eyes, ears, and hands of electronic systems and allow them to capture the state of the environment. The capture and processing of sensor inputs is a delicate process that requires understanding of the signal details. Integration of sensor functions onto silicon has brought about improved performance, better signal handling, and lower total system cost. MEMS (microelectromechanical systems) sensors have opened up entire new areas and applications. In this session, the fundamental MEMS sensor concept of moving fingers that form a variable capacitor is covered, along with how it is turned into a usable motion signal. Adaptations for multiaccess sensing, rotational sensing, and even sound sensing, along with concepts of how these devices are tested and calibrated, are covered.

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Sensors for Low Level Signal Acquisition - VE2013

  1. 1. Sensors for Low Level Signal Acquisition Advanced Techniques of Higher Performance Signal Processing David Kress – Director of Technical Marketing Nitzan Gadish – MEMS Applications Engineer
  2. 2. 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
  3. 3. 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
  4. 4. The Real World Is NOT Digital 5
  5. 5. Analog to Electronic Signal Processing SENSOR (INPUT) DIGITAL PROCESSOR AMP CONVERTER ACTUATOR (OUTPUT) AMP CONVERTER 6
  6. 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
  7. 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
  8. 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
  9. 9. Silicon Sensors Sensor Type Output Temperature Voltage/current Photodiode Current Strain gauge Resistance Microphone Capacitance Rotation Capacitance Antenna RF -- Inductance Acceleration Capacitance 10
  10. 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“
  11. 11. 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 Typical Output
  12. 12. Basic Relationships for Semiconductor Temperature Sensors IC IC VBE VN ∆VBE VBE VN kT q N= − = ln( ) VBE kT q IC IS =      ln       = S C N IN I q kT V × ln INDEPENDENT OF IC, IS ONE TRANSISTOR N TRANSISTORS 13
  13. 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 VN kT q N= − = ln( ) 14
  14. 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
  15. 15. 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
  16. 16. 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
  17. 17. 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
  18. 18. Thermocouple Very low level (µV/ºC) Nonlinear Difficult to handle Wires need insulation Susceptible to noise Fragile 21
  19. 19. 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
  20. 20. Thermocouple Seebeck Coefficient vs. Temperature -250 0 250 500 750 1000 1250 1500 1750 0 10 20 30 40 50 60 70 SEEBECKCOEFFICIENT-µV/°C TEMPERATURE (°C) TYPE J TYPE K TYPE S -250 0 250 500 750 1000 1250 1500 1750 0 10 20 30 40 50 60 70 SEEBECKCOEFFICIENT-µV/°C TEMPERATURE (°C) TYPE J TYPE K TYPE S 23
  21. 21. Thermocouple Basics 24 T1 METAL A METAL B THERMOELECTRIC EMF RMETAL A METAL A R = TOTAL CIRCUIT RESISTANCE I = (V1 – V2) / R V1 T1 V2T2 V1 – V2 METAL B METAL A METAL A V1 V1 T1 T1 T2 T2 V2 V2 V METAL AMETAL A COPPER COPPER METAL BMETAL 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 RMETAL A METAL A R = TOTAL CIRCUIT RESISTANCE I = (V1 – V2) / R V1 T1 V2T2 V1 – V2 METAL B METAL A METAL A V1 V1 T1 T1 T2 T2 V2 V2 V METAL A COPPER COPPER METAL BMETAL B T3 T4 V = V1 – V2, IF T3 = T4 A. THERMOELECTRIC VOLTAGE B. THERMOCOUPLE C. THERMOCOUPLE MEASUREMENT D. THERMOCOUPLE MEASUREMENT I V1
  22. 22. Using a Temperature Sensor for Cold-Junction Compensations TEMPERATURE COMPENSATION CIRCUIT TEMP SENSOR T2V(T2)T1 V(T1) V(OUT) V(COMP) SAME TEMP METAL A METAL B METAL A COPPERCOPPER ISOTHERMAL BLOCK V(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) TEMPERATURE COMPENSATION CIRCUIT TEMP SENSOR T2V(T2)T1 V(T1) V(OUT) V(COMP) SAME TEMP METAL A METAL B METAL A COPPERCOPPER ISOTHERMAL BLOCK V(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
  23. 23. 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
  24. 24. 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 COLD JUNCTION COMPENSATION THERMO- COUPLE 1MΩ 100Ω 49.9kΩ 0.01µF 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 1.0µF 100Ω SERIAL INTERFACE INTERNAL CLOCK 16-BIT ADC GND REFIN AD7790 DIGITAL PGABUF VDD VDD GND +5VADR441 +5V +2.5VVIN VOUT GND 10598-001
  25. 25. 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
  26. 26. High Accuracy Applications CJC using ADT7320 29 ADT7320 for cold- junction temperature measurement Thermocouple isothermal connector ADT7320 mounted on Flex PCB Σ-Δ ADC
  27. 27. 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 SERIAL INTERFACE AND CONTROL LOGIC INTERNAL CLOCK CLK SIGMADELTA ADC IOUT1 MUX IN-AMP REFIN(+) REFIN(-)BANDGAP REFERENCE GND SPI SERIAL INTERFACE IOVDD VDD GND IOUT2 REFIN AIN1 RREF EXCITATION CURRENTS
  28. 28. 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
  29. 29. Photodiode Equivalent Circuit 33 PHOTO CURRENT IDEAL DIODE INCIDENT LIGHT RSH(T) 100kΩ - 100GΩ CJ Note: RSH halves every 10°C temperature rise
  30. 30. 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 – +
  31. 31. 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
  32. 32. Current-to-Voltage Converter (Simplified) 36 ISC = 30pA (0.001 fc) + _ R = 1000MΩ VOUT = 30mV SENSITIVITY: 1mV / pA
  33. 33. 38
  34. 34. Photodiode Amplifier Design Choices 39
  35. 35. Photodiode Amplifier Design Result 40
  36. 36. 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 0.1µF 0.1µF 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 24.9kΩ 2.5kΩ 1kΩ 33Ω 33Ω +5V –5V +5V –5V TP3 TP2 ADR441 +5V +2.5VVIN VOUT GND GND TP1 10599-001 FastFET Opamp Ib = 1pA BW = 145MHz Vn = 7nV/rtHz Cn = 0.6fA/rtHz
  37. 37. 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.
  38. 38. 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
  39. 39. 44 MEMS Sensors are Everywhere Health and Fitness Products Smartphones Automotive Safety and Infotainment Precision Agriculture Avionics and Navigation Fleet Management Asset Tracking
  40. 40. What you can measure: 45
  41. 41. What you can measure: 46 Linear Motion
  42. 42. ADI’s Motion Signal Processing ™ Enables… Motion Sensing 47 Fleet management Alarm systems Motion control and orientation of industrial robots Precision agriculture
  43. 43. What you can measure: 48 Tilt
  44. 44. 49 ADI’s Motion Signal Processing ™ Enables… Tilt Sensing Leveling Horizon detection in cameras
  45. 45. What you can measure: 50 Vibration & Shock
  46. 46. 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
  47. 47. What you can measure: 52 Rotation
  48. 48. 53 ADI’s Motion Signal Processing ™ Enables… Rotation Sensing Platform/antenna stabilization: Industrial, maritime, avionics, communications Digital camera OIS Automotive Rollover Detection
  49. 49. Measuring complex motion: 54 Inertial Measurement Unit
  50. 50. 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
  51. 51. Measuring motion 56
  52. 52. ADI’s Inertial MEMS Sensors: Accelerometers measure linear motion Gyroscopes measure rotation 57
  53. 53. ADI MEMS SENSORS: A brief history… 58
  54. 54. MEMS at ADI: In the beginning… Concept began in ~1986 Market: airbag sensors
  55. 55. 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
  56. 56. A little history… The first airbags used ball-in-tube sensors. Concept began in ~1986 Market: airbag sensors
  57. 57. 63 How Do Accelerometers Work? Strong M a s s Weak M a s s No Deceleration M a s s
  58. 58. How Do Accelerometers Work? constant
  59. 59. 65 How Do MEMS Accelerometers Work? Single axis accelerometer in silicon has the same components  Left / Right (X-axis) XLeft RightM a s s Proof Mass Suspension Spring Suspension Spring Motion (ca. 1992-1995)
  60. 60. How Do iMEMS Accelerometers Work? Single axis accelerometer in silicon has the same components  Left/right (x-axis) 66 (ca. 1992-1995)
  61. 61. 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)
  62. 62. 68 How Do MEMS Accelerometers Work? Measurement of deflection is done with variable differential capacitor "finger sets" (ca. 1992-1995)
  63. 63. 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
  64. 64. What accelerometers measure: 70
  65. 65. 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
  66. 66. 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 ±200 g 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
  67. 67. 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
  68. 68. ADI’s Inertial MEMS Sensors: Accelerometers measure linear motion Gyroscopes measure rotation 74
  69. 69. 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
  70. 70. 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
  71. 71. 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
  72. 72. 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
  73. 73. RESONATOR MOTION Gyro Principle of Operation 79 ACCELEROMETER TETHER RESONATOR TETHER ACCELEROMETER FRAME RESONATOR CORIOLISACCELERATION APPLIED ROTATION ANCHOR
  74. 74. Gyro Principle of Operation 80 No Rotation
  75. 75. Gyro Principle of Operation 81 Rotation Applied
  76. 76. 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
  77. 77. 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
  78. 78. Gyro Principle of Operation 85 Vibration Applied - + Cancelled out
  79. 79. Photograph of Mechanical Sensor 86
  80. 80. Problems With Single Mass Gyros… …are also problems with dual-mass gyros, just to a lesser extent. That wasn’t good enough for us.
  81. 81. The Latest
  82. 82. 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
  83. 83. 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
  84. 84. MEMS Microphone 91 Just another accelerometer in disguise
  85. 85. 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
  86. 86. 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
  87. 87. 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
  88. 88. 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!
  89. 89. Why Use MEMS Microphones? Less Sensitivity Variation vs. Temperature ECM vs. ADMP441 96 Change (in dB) from original sensitivity
  90. 90. 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
  91. 91. 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
  92. 92. 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
  93. 93. Tweet it out! @ADI_News #ADIDC13 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
  94. 94. 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
  95. 95. 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
  96. 96. 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
  97. 97. 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 BOARDSOFTWARE OUTPUT DISPLAY EVAL-CN0189-SDPZ
  98. 98. 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

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