1. Today’s Smart Sensors
January 25, 2013 Randy Frank

2. Agenda Pressure Temperature Proximity
Application Specific: Tire Pressure Monitoring
Accelerometer
Gyroscope
Accelerometer & Magnetometer
9-axis IMU

3. Smart Pressure Sensor MEMS Relative Pressure Sensor
Pressure and Vacuum
1 Bar Full Scale
Analog output or SENT Protocol
Integrated Signal Processing
16-Bit ADC
16-Bit MCU

4. Smart Pressure Sensor
High accuracy relative pressure sensor (+/-1.5%FSO)
Ratiometric Analog Output or digital SENT output (SAE J-2716 spec dated Jan 2010)
Large automotive temperature range (-40C to 150C)
Automotive qualified and automotive diagnostic features

5. Temperature Non-contact measurement Design goals: small and low power
Existing IR design
Non-contact measurement
Design goals: small and low power
1.6 mm x 1.6 mm: 95% smaller than existing solutions
Draws 90% less power than the competition
240 uA quiescent current
1 uA in shutdown mode
Texas Instruments
TMP006

6. Temperature Additional specifications
Temperature range: -40°C to +125°C
Local sensor accuracy: +/- 0.5°C (typical)
Passive IR sensor accuracy: +/- 1°C (typical)
Digital solution
I2C/SMBus digital interface

7. Temperature Integrates 5 discrete components:
1 MEMS thermopile sensor 2 Signal conditioning
3 16-bit ADC 4 Local temperature sensor
5 Voltage references

8. Proximity Sensor Semtech
The SX9300 is the world’s first dual-channel capacitive Specific Absorption Rate (SAR) controller that accurately discriminates between an inanimate object and human body proximity.

9. Proximity Sensor Semtech SX9300 20mm detection distance
400kHz I2C Serial Interface
Automatic Calibration
3 x 3mm Thin QFN package

10. Application Specific Example: Tire Pressure Monitoring System
Pressure and temperature sensors
X- and Z-axis accelerometers
RF Transmitter 315/434 MHz PLL-based RF transmitter
MCU 8-bit S08 core MCU
16 KB flash
512B RAM

11. Application Specific Example: TPMS

12. Accelerometer Integration of: 3-axis MEMS accelerometer
32-bit embedded ColdFire microcontroller
Flash memory
Dedicated architecture to manage other sensors

13. Accelerometer

14. Gyroscope STMicroelectronics L3G4IS
a global dual-core, 3-axis gyroscope capable of handling both user-motion recognition and camera image stabilization
Three selectable full-scales (250/500/2000 dps) for gaming applications
Embeds a temperature sensor
4x4x1 mm package

15. Gyroscope STMicroelectronics L3G4IS
Includes power-down and sleep modes
Embedded FIFO (first-in first-out) memory block for smarter power management.

16. Accelerometer & Magnetometer
Kionix KMX61G
High performance accelerometer-magnetometer sensor
With integrated sensor fusion software
Emulated gyro outputs with up to 14-bit resolution

17. Accelerometer & Magnetometer
Kionix KMX61G
3x3x0.9mm package size
User-programmable ±2g/±4g/±8g full-scale accelerometer range
±1200μT total magnetometer measurement range
Avoids the power consumption of gyro (550μA)

18. InvenSense MPU-9250 9-axis MotionTracking device
3x3x1mm QFN package System in Package (SiP)
Combines
MPU-6500 that contains a 3-axis gyroscope, a 3-axis accelerometer, and an onboard Digital Motion Processor (DMP) capable of processing complex MotionFusion algorithms
AK axis digital compass.

19. What can we expect?
What can sensor suppliers cram into a 3 x3 mm footprint?
A 2 x 2- mm footprint?
Certainly more software

20. Summary Presented 8 Smart Sensors Sensor with integrated MCU plus
All include extra systems aspects
All plug into a digital system
Software is either integrated or part of suppliers’ total system approach

21. Topics Covered This Week
Monday
Basics of sensor compensation for piezoresistive sensors
Tuesday
Basics of Sensor Compensation for Capacitive Sensors
Wednesday
A case study of smart sensor development
Thursday
Transitioning from analog sensing to the digital control world
Friday
Today’s smart sensors