a case study of mems industrial products

a case study of mems industrial products
M.Tech 2nd semester
Applied Electronics & Instrumentation
MEMS (Micro Electro Mechanical Systems) is a technology that can be defined
generally as miniaturised mechanical and electromechanical systems that are made using the
techniques of micro fabrication. The physical dimension of MEMS devices can vary from well
below one micron to several millimetres. The pioneer of MEMS industry was ‘hp’ (Hewlett
Packard). After that so many industrial giants entered in to the world of MEMS device
fabrication and became successful. The following list shows the leading manufacturers of
MEMS devices and their turnover in the year 2012*.
Company name
Founded year
ST Micro electronics
Robert Bosch
Texas Instruments
Hewlett Packard
Knowles Electronics
Avago Technologies
*courtesy of Yole development
**spin off from Motorola
Turnover in the year
2012(Million USD)
Growth rate (%)
(year 2012)
The most demanded MEMS components in the market are accelerometers
The following list shows different MEMS components and their market share***
MEMS device
IJ heads
Pressure sensors
Micro fluidics
Market share (2012)
Si microphones
*** courtesy Yole development
Different MEMS components are introduced in the following pages.
Company name
Component Name
Cost of product
: ST Microelectronics
: (5-6 )US$
: 4x4x1.5 mm
: LGA 16 L
The LGA (Land Grid Array) is a type of surface mount packaging for integrated circuits
that is notable for having the pins on the socket rather than the integrated circuits. An LGA can
be electrically connected to a printed circuit board either by the use of socket or by soldering
1)2.4v to 3.6v single supply operation
2) ±2g/±6g user selectable full scale
3) Output voltage, offset and sensitivity are ratio metric. to supply voltage
4) Low power consumption
5) Embedded self test
6)High shock survivability (10000g)
Fabrication Details
: The sensing element capable of detecting the
acceleration is manufactured using a dedicated process developed by ST to produce
inertial sensors and actuators in silicon. The IC interface is manufactured using an ST
proprietary CMOS process with high level of integration. The dedicated circuit is
trimmed to better n]match the sensing element characteristics
Product Description
: The LIS344ALH has a dynamically user selectable full
scale of ±2g/±6g and it is capable of measuring accelerations over a maximum
bandwidth of 1.8 kHz for all axes. the self test capability allow the user to check the
functioning of the system. It is guaranteed to operate over an extended temperature range
of -40oC to +85oC.
Bottom view of LIS344ALH
1) Gaming and Virtual reality input devices
2) Anti theft systems and inertial navigation
3) Appliances and robotics
Submitted By:
Rahul K K
• Company name
: Bosch Sensortec
• Component Name
: BMP 180
Cost of product
: 9 US$
: (3.6x3.8x0.93) mm3
panel view of BMP 180 MEMS pressure sensor
1) Digital two wire (I²C, TWI, "Wire") interface
2) Wide barometric pressure range
3) Flexible supply voltage range (1.8V to 3.6V)
4) Ultra low power consumption (9.9 µW) up to 3µA current and optimum voltage as
5) Factory-calibrated .
6) Includes temperature sensor.
7) Low-profile with a small footprint.
Pressure range
Average current consumption
3µA(ultra low power mode)
32µA(advanced mode)
Power consumption
9.9 µW(ultra low power mode)
Peak current
105.6 µW(advanced mode)
16.5 µW(standard mode)
Stand by current
0.1 µA
Supply voltage VDDIO
Supply voltage VDD
Pressure conversion time
5ms(standard mode)
Operation temperature range
Full accuracy
data transfer rate
(−40 + 85) C
(0 + 65) C
3.4 Mhz,max
Package type/pin numbers
Package dimensions
Fabrication Details
• Product Description
: Bosch Process.
:-This is a breakout board for the Bosch BMP180
high-precision, low-power digital barometer. The BMP180 offers a pressure measuring range of
300 to 1100 hPa with an accuracy down to 0.02 hPa in advanced resolution mode. It is based on
piezo-resistive technology for high accuracy, ruggedness and long term stability. These come
factory-calibrated, with the calibration coefficients already stored in ROM.
This breadboard-friendly board breaks out every pin to a 5-pin 0.1" pitch header. VCC
can be from 1.8V to 3.6V and is 5V tolerant; typically it is run on a clean, regulated 3.3V supply.
The analog and digital supplies are tied to a single header pin, but are separately decoupled. It
connects to a microcontroller via I²C bus
Pin No:
Bottom View
1)In advanced mobile devices like smart phones, tablet PCs, sports devices etc.
2)Indoor navigation
3)GPS enhancement for dead-reckoning, slope detection etc.
4)Sport devices for altitude profile.
5) Weather forecast.
6)Vertical velocity indicator(rise/sink speed).
Submitted By:
Jinu M. Thomas
• Company name
• Component Name
• Cost of product
• Dimensions
• Packaging
: Analog Devices, Inc
: ADXL001 Accelerometer
: 33 US$
: 4.6x5.2x2.2mm
1)High performance accelerometer
±70 g, ±250 g, and ±500 g wideband ranges available
22 kHz resonant frequency structure
High linearity: 0.2% of full scale
Low noise: 4 mg/√Hz
2)Frequency response down to dc
3)Full differential signal processing
4)High resistance to EMI/RFI
5)Complete electromechanical self-test
6)Output ratiometric to supply
7)Low power consumption: 2.5mA typical.
8)8-terminal, hermetic ceramic, LCC package
Fabrication details : Not Available
Product Description :
The ADXL001 is a major advance over previous generations of accelerometers
providing high performance and wide bandwidth. This part is ideal for industrial,
medical, and military applications where wide bandwidth, small size, low power, and
robust performance are essential.
Using Analog Devices, Inc. proprietary fifth-generation iMEMs® process enables
the ADXL001 to provide the desired dynamic range that extends from ±70 g to ±500 g in
combination with 22 kHz of bandwidth. The accelerometer output channel passes through
a wide bandwidth differential-to-single-ended converter, which allows access to the full
mechanical performance of the sensor.
The part can operate on voltage supplies from 3.3 V to 5 V.
The ADXL001 also has a self-test (ST) pin that can be asserted to verify the full
electromechanical signal chain for the accelerometer channel.
The ADXL001 is available in the industry-standard 8-terminal LCC and is rated
to work over the extended industrial temperature range (−40°C to +125°C).
Vibration monitoring
Shock detection
Sports diagnostic equipment
Medical instrumentation
Industrial monitoring
Submitted By:
Brijesh Varghese
• Company name
: InvenSense
Component Name
: MPU-6050 3-axis MEMS accelerometer & gyroscope
Cost of product
: 5 US$
: 4x4x0.9 mm
: LGA with JEDEC type extension
LGA 4x4x0.9 mm
1) 2.4v to 3.6v single supply operation
2) ±2g/±4/±8/±16g user selectable full scale
3) Output voltage, offset and sensitivity are ratio-metric. to supply voltage
4) Low power consumption
5) Tap detection
6) User-programmable interrupts
7) User programmable scale range of ±250, ±500, ±1000, and ±2000°/sec
8) Digitally-programmable low-pass filter
9) Gyroscope operating current: 3.6mA
10) Integrated 16-bit ADCs enable simultaneous sampling of gyros
11) Standby current: 5µA
12) 9-Axis Motion Fusion by the on-chip Digital Motion Processor (DMP)
13) Auxiliary master I2C bus for reading data from external sensors (e.g., magnetometer)
14) Digitally-programmable low-pass filters
Top view of MPU-6050
Fabrication details:
Not available
Product description:
Not available
1) Location based services, points of interest, and dead reckoning
2) Handset and portable gaming
3) Motion-based game controllers
4) 3D remote controls for Internet connected DTVs and set top boxes, 3D mice
5) Wearable sensors for health, fitness and sports Toys
Submitted By:
Dhanish Vijayan
• Company name
:Analog Devices
Product name
Cost of product
:4.5-5 US$
1) Ultralow power
2) User-selectable resolution
3) Free-fall detection
4) Supply voltage range: 2.0 V to 3.6 V
5) I/O voltage range: 1.7 V to VS
6) SPI (3- and 4-wire) and I2C digital interface
7) Wide temperature range (−40°C to +85°C)
8) 10,000 g shock survival
9) Pb free/RoHS compliant
10) Small and thin
Fabrication Details:
Not available.
Product description:- The ADXL345 is a small, thin, ultralow power, 3-axis
accelerometer with high resolution (13-bit) measurement at up to ±16 g. Digital output
data is formatted as 16-bit twos complement and is accessible through either a SPI (3- or
4-wire) or I2C digital interface.
The ADXL345 is well suited for mobile device applications. It measures the static
acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration
resulting from motion or shock. Its high resolution (3.9 mg/LSB) enables measurement of
inclination changes less than 1.0°.
Several special sensing functions are provided.
Activity and inactivity sensing detect the presence or lack of motion by comparing the
acceleration on any axis with user-set thresholds. Tap sensing detects single and double
taps in any direction. Free-fall sensing detects if the device is falling. These functions can
be mapped individually to either of two interrupt output pins. An integrated, patent
pending memory management system with 32-level first in, first out (FIFO) buffer can be
used to store data to minimize host processor activity and lower overall system power
consumption. Low power modes enable intelligent motion-based power management
with threshold sensing and active acceleration measurement at extremely low power
Medical instrumentation
Gaming and pointing devices
Industrial instrumentation
Personal navigation devices
Submitted By:
Mohammed Shaffi J
Company name
:Analog Devices
Component Name
: ADXL330
Cost of product
: 5-6 US$
: 4x4x1.45 mm
Product Description
The ADXL330 is a small, thin, low power, complete 3-axis accelerometer with
signal conditioned voltage outputs, all on a single monolithic IC. The product measures
acceleration with a minimum full-scale range of ±3 g. It can measure the static
acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration
resulting from motion, shock, or vibration.
1)1.8v to 3.6v single supply operation
2) ±3g user selectable full scale
3) Low power consumption: 180 µA at VS = 1.8 V (typical)
4) Embedded self test
5)High shock survivability (10000g)
6) BW adjustment with a single capacitor per axis
7)Operating Temp. range -25 to+70 oC
Functional Block Diagram
Pin Configuration
Pin Description
Package description
1) Gaming and Virtual reality input devices
2) Mobile devices like smart phones, tablet PCs, sports devices etc.
3) Gaming systems
4)Disk drive protection
5)Image stabilization.
6) Appliances and robotics
Submitted By:
Amanathulla M
Company name
: ST Microelectronics
Component Name
Cost of product
: 15-20 US$
: 3x5x1 mm
: LGA 14 L
Power rating
: 0.396mW at normal operation
3.6µW at low power mode.
Product description:
The LSM303DLHC is a system-in-package featuring a 3D digital linear acceleration
sensor and a 3D digital magnetic sensor. LSM303DLHC has linear acceleration fullscales of ±2g / ±4g / ±8g / ±16g and a magnetic field full- scale of ±1.3 / ±1.9 / ±2.5 /
±4.0 / ±4.7 / ±5.6 / ±8.1 gauss. All full-scales available are fully selectable by the user.
LSM303DLHC includes an I2C serial bus interface that supports standard and fast mode
100 kHz and 400kHz. The system can be configured to generate interrupt signals by
inertial wake- up/free-fall events as well as by the position of the device itself.
Thresholds and timing of interrupt generators are programmable by the end user on the
fly. Magnetic and accelerometer parts can be enabled or put into power-down mode
separately. The LSM303DLHC is available in a plastic land grid array package (LGA)
and is guaranteed to operate over an extended temperature range from -40 °C to +85 °C.
1) 3 magnetic field channels and 3 acceleration channels
2) From ±1.3 to ±8.1 gauss magnetic field full- scale
3) ±2g/±4g/±8g/±16g selectable full-scale
4) 16 bit data output
5) I2C serial interface
6) Analog supply voltage 2.16 V to 3.6 V
7) Power-down mode/ low-power mode
8) 2 independent programmable interrupt generators for free-fall and motion
9) Embedded temperature sensor
10) 6D/4D orientation detection
• Fabrication Details:
The sensing element is manufactured using a dedicated process developed by ST
to produce inertial sensors and actuators in silicon. The IC interface is manufactured using
an ST proprietary CMOS process with high level of integration. The dedicated circuit is
trimmed to better match the sensing element characteristics
Bottom view of LSM 303DLHC
1) Compensated compass
2) Map rotation
3) Position detection
4) Motion-activated functions
5) Free-fall detection
6) Click/double click recognition
7) Pedometer
8) Intelligent power-saving for handheld devices
9) Display orientation
10) Gaming and virtual reality input devices
11) Impact recognition and logging
12) Vibration monitoring and compensation
Submitted By:
Amrutha K
Company name
Component Name
Cost of product
: 5-6 US$
: (6 x 6 mm)
: QFN48
Product Description
The STMT05E device represents a marked improvement over competing
technologies by providing an optimal mix of low power, small size, feature flexibility
with unmatched true multi-touch performance in a single-chip touchscreen controller.
The FingerTip STMT05E uses a unique capacitance to voltage conversion acquisition
engine to implement the S-Touch capacitive sensing method. Coupled with the flexibility
offered by the internal processor engine, the entire touch-screen sensing solution can
measure, classify and track a single finger touch with fast report rate and response times
on 240 nodes. Built-in movement tracking engine tracks greater than 10 independent
touch movements. The acquisition engine uses an optimal measurement approach to
ensure almost complete immunity from parasitic capacitance on the receiver inputs (sense
lines). The engine includes sufficient dynamic range to cope with touch-screens of
different size and configuration. This offers great flexibility to use with multiple touchscreens with different ITO designs and overlay materials. One and two layer ITO sensors
are possible using glass or PET substrates.
The STMT05E's capacitive analog front-end provides enhanced noise suppression
capabilities for various noise sources such as display, human body captured noise, system
generated noise and severe common mode noise introduced by battery chargers. ST’s
advanced capacitive sensing technology coupled with a powerful digital 32-bit DSP
engine is able to address common mode noise to provide high level of noise immunity
without reducing the overall touch performance in terms of response time, frame rate and
power consumption.
The device has external SYNC pin for LCD noise filtering for an "on-cell"
display touch-screen technology. The synchronization of the signal acquisition with the
LCD SYNC signal helps in removal of LCD noise. This benefits the touch module maker
to employ glass screens with ITO to be used without any GND shield that can
significantly reduce the cost of the touch module. The STMT05E supports multiple input
types including stylus detection (up to 2 mm) for smooth handwriting capability on
touch-screens while detecting and rejecting large area such as palm or hand. The device
also supports touch-keys using the same ITO.
1)True multi-touch:
– Independent XY tracking with 10 simultaneous touches in real time
– Up to 12 force and 20 sense channels
2)Single chip solution:
– Up to 5 inches screen size
– Supports multiple touchscreen configurations including touch keys with no external
components on touch channels
3) High SNR:
– Common mode charger noise rejection up to 40 Vpp
– Advanced filtering techniques for strong noise immunity
4) Fast report rate: > 150 Hz
5) High response time: < 2x report rate
6) Power consumption:
– 7 mW in active mode (multi-touch)
– 5 µW in sleep mode
7) Power supply scheme:
– 2.8 V to 5 V AVDD and 1.8 V DVDD
8)32-bit RISC processor
– Flexibility for customer code implementation
– Allows customization of proprietary touch pattern and gestures
9) Large area recognition and rejection
10) Advanced signal processing and calibration:
– Water recovery, self-calibration with autodrift compensation and fast start-up
– Hardware coordinate scalar to match touch-screen and display resolution
– Supports axis flipping and axis switch-over for portrait and landscape modes
11) Sensor types:
– Works with plastic or glass sensors, with different types of sensor patterns with or
without ground shield
– Supports on-cell, laminated and touch-onlens touch display
12) Serial interface:
– Supports high speed I2C and SPI
– 3.3 V tolerant interface for I2C and SPI
Package description
Flat no-leads packages such as QFN (quad-flat no-leads) and DFN (dual-flat no-leads)
physically and electrically connect integrated circuits to printed circuit boards. Flat no-leads, also
known as micro lead frame (MLP) and SON (small-outline no leads), is a surface-mount
technology, one of several package technologies that connect ICs to the surfaces
of PCBs without through-holes. Flat no-lead is a near chip scale package plastic encapsulated
package made with a planar copper lead frame substrate. Perimeter lands on the package bottom
provide electrical connections to the PCB Flat no-lead packages include an exposed thermal pad
to improve heat transfer out of the IC (into the PCB). Heat transfer can be further facilitated by
metal vias in the thermal pad The QFN package is similar to the quad-flat package, and a ball
grid array.
0.4mm pitch and 0.55 mm thick and up to 5 inches screen size
Main application lies in touch screen mobile phone with stylus detection (up to 2 mm) for
smooth handwriting capability on touch screens while detecting and rejecting large area
such as palm or hand. The device also supports touch keys using the same ITO.
Submitted By:
Vaisakhan K R
Company name
: Analog Devices
Component Name
: ADXRS646
Cost of product
: (58-64)US$
: 7×7 ×3 mm
: 32 Lead CBGA
Product description:
The ADXRS646 is a high performance angular rate sensor (gyroscope)
that offers excellent vibration immunity. The ADXRS646 offers superior vibration
immunity and acceleration rejection as well as a low bias drift of 12°/hr (typical),
enabling it to offer rate sensing in harsh environments where shock and vibration are
present. An advanced, differential, quad sensor design provides the improved
acceleration and vibration rejection. The output signal, RATEOUT, is a voltage
proportional to angular rate about the axis normal to the top surface of the package. The
measurement range is a minimum of ±250°/sec. The output is ratiometric with respect
to a provided reference supply. Other external capacitors are required for operation.
1. 12°/hr bias stability
2. Z-axis (yaw rate) response
3. 0.01°/√sec angle random walk
4. High vibration rejection over wide frequency
5. Measurement range extendable to a maximum of ±450°/sec
6. 10,000 g powered shock survivability
7. Ratiometric to referenced supply
8. 6 V single-supply operation
9. −40°C to +105°C operation
10. Self-test on digital command
11. Ultrasmall and light (<0.15 cc, <0.5 gram)
12. Temperature sensor output
Complete rate gyroscope on a single chip
1) Computer pointing devices
2) Ship stabilizers
3) Severe mechanical environments
4) Robotics
Submitted By:
Nithin K Kurian
• Company name
• Component Name
: MMC3416xPJ
Cost of product
: 1.5 US$
: 1.6x1.6x0.6 mm
MMC3416xPJ magnetometer used in Wrist watches
1)Fully integrated 3-axis magnetic sensor and electronic circuits requiring fewer
external components
2) Superior Dynamic Range and Accuracy:
±16 G FSR with 16/14 bits operation
0.5 mG/2 mG per LSB resolution in 16/14 bits operation mode
1.5 mG total RMS noise
Enables heading accuracy of ±1º
3) Max output data rate of 800 Hz (12 bits mode)
4) Ultra Small Low profile package (1.6x1.6x0.6 mm)
5) SET/RESET function
Allows for elimination of temperature variation induced offset error (Null field
Clears the sensors of residual magnetization resulting from strong external fields
6) On-chip sensitivity compensation
7) Low power consumption (140 µA at 7 Hz )
8) 1µA (max) power down function
9) I2C Slave, FAST (≤400 KHz) mode
10) 1.62 V~3.6 V wide power supply operation supported, 1.8 V I/O
Fabrication Details
: Not available
Product description:-
The MMC3416xPJ is a complete 3-axis magnetic sensor with
on-chip signal processing and integrated I2C bus. The device can be connected directly
to a microprocessor, eliminating the need for A/D converters or timing resources. It can
measure magnetic fields within the full scale range of ±16 Gauss (G), with 0.5 mG/2 mG
per LSB resolution for 16/14 bits operation mode and 1.5 mG total RMS noise level,
enabling heading accuracy of 1º in electronic compass applications. Contact MEMSIC
for access to advanced calibration and tilt-compensation algorithms. An integrated
SET/RESET function provides for the elimination of error due to Null Field output
change with temperature. In addition it clears the sensors of any residual magnetic
polarization resulting from exposure to strong external magnets. The SET/RESET
function can be performed for each measurement or periodically as the specific
application requires. The MMC3416xPJ is packaged in an ultra small low profile LGA
package (1.6 x 1.6 x 0.6 mm,) and with an operating temperature range from -40 º C to
+85 º C. The MMC3416xPJ provides an I2C digital output with 400 KHz, fast mode
Principle of operation:The Anisotropic Magneto-Resistive (AMR) sensors are special resistors made of
permalloy thin film deposited on a silicon wafer. During manufacturing, a strong
magnetic field is applied to the film to orient its magnetic domains in the same direction,
establishing a magnetization vector. Subsequently, an external magnetic field applied
perpendicularly to the sides of the film causes the magnetization to rotate and change
angle. This effect causes the film’s resistance to vary with the intensity of the applied
magnetic field. The MEMSIC AMR sensor is incorporated into a Wheatstone bridge
configuration to maximize Signal to Noise ratio. A change in magnetic field produces a
proportional change in differential voltage across the
Wheatstone bridge However, the influence of a strong magnetic field (more than 25 G) in
any direction could upset, or flip, the polarity of the film, thus changing the sensor
characteristics. A strong restoring magnetic field must be applied momentarily to restore,
or set, the sensor characteristics. The MEMSIC magnetic sensor has an on-chip
magnetically coupled strap: a SET/RESET strap pulsed with a high current, to provide
the restoring magnetic field.
Applications:1) Electronic Compassing in cellular phones and tablets, pedestrian navigation,
gaming controls, wristwatches, in-vehicle GPS navigation
2) Linear and rotational position Sensing
3) Magnetic field measuring applications.
Submitted By:
Jithya K R
Company name
: VectorNav Technologies
Component Name
: VectorNav VN-200 GPS/INS
Cost of product
: (5-6) US$
: Dimensions: 24 x 22 x 3 mm
: Surface Mount Package (30-pin LGA)
Product Description
The VN-200, the world’s smallest & lightest, high-performance GPS-Aided
Inertial Navigation System (GPS/INS).Combining an advanced GPS module with the
latest in MEMS inertial & pressure sensor technology, the patent pending VN-200
provides unprecedented opportunities for embedded navigation in a footprint no larger
than a postage stamp.
1) On-Board Extended Kalman Filter Running at 200 Hz
2) Coupled Position, Velocity & Attitude Estimates
3) Dynamic Accuracy better than 0.25° in Pitch/Roll, 0.75°in Heading
4) On-Board Pressure Sensor & U-Blox GPS Receiver
5) Compatible with external GPS, pressure and magnetic measurements
6) Individually Calibrated for Bias, Scale Factor, Misalignment, & Gyro GSensitivity
7) Available with Full Temperature Compensation (-40°C to +85°C)
8) Weight: 3 grams
Functional Block Diagram
Packaging information :
The VN-200
200 is the smallest, lightest, and lowest power GPS/INS available on the
market. The sensor package and all electronics are housed in a rugged aluminum
enclosure. Precision alignment holes are provided to ensure accurate installation. A 1010
pin locking connector is used to provide a reliable connection in severe high vibration or
shock conditions.
Technical specifications:
1. Motor sports
2. Unmanned vehicles
3. Camera stabilization
4. Marine antenna stabilization
Submitted By:
Aswin Shenoy A
Company name
: Texas Instruments
Component Name
: DLP 5500
Cost of product
: (4-5) US$
: 2D array (1024x768) of Aluminium micromirrors
Micromirror size 16µm2
: 149 Micro Pin Grid Array
The PGA (Pin Grid Array) is a type of integrated circuit
packaging. In a PGA, the package is square or rectangular, and the pins are arranged in a
regular array on the under-side of the package. The pins are commonly spaced 1.27mm apart,
may or may not cover the entire under-side of the package.
: 1) 3.6V single supply operation
2) Peak Current 750mA
3)power consumption 2.7W
Fabrication Details
1) bulk micro-machining
2) Al - for mirror, Si nitride for isolation
3) CMOS substrate
4) SiO2 and Al are deposited on CMOS substrate
Micro Pin Grid Array
Mechanical Dimension
3D Machine Vision
3D Optical Measurement
Industrial and Medical Imaging
Medical Instrumentation
Digital Exposure systems
Submitted By:
Vani M
• Company Name
: Analog Devices
• Component Name
:ADXL193 (Silicon capacitive accelerometer)
• Cost of Product
7.5 US$
• Dimensions
:5x5x2 mm
• Packaging
The ADXL193 is a low power, complete single-axis accelerometer with signal
conditioned voltage outputs that are all on a single monolithic IC. This product measures
acceleration with a full-scale range of ±120 g. It can also measure both dynamic acceleration
(vibration) and static acceleration (gravity). ADXL193 chip is shown below. It is a fourth-
Fig: ADXL193 Chip
generation surface micromachined MEMS accelerometer from ADI with enhanced performance
and lower cost. Designed for use in front and side impact airbag applications, this product also
provides a complete cost-effective solution useful for a wide variety of other applications.
ADXL193 is temperature stable and accurate over the automotive temperature range, with a selftest feature that fully exercises all the mechanical and electrical elements of the sensor with a
digital signal applied to a single pin. Its cost is `450.
Sensing principle:
Capacitance change is the most widely used principle in microaccelerometers. A capacitor sensor
contains a movable plate and a fixed plate. The input signal is applied to the movable plate. As
the plate moves, the capacitance value change according to the equation is:
c is the capacitance
Ԑ is the permittivity of dielectric medium
A is the overlapping area
d is the distance between electrodes
A MEMS capacitor structure is shown in figure below. The component consists of a substrate
and two electrodes separated by a cavity which forms the dielectric.
Fig: A MEMS Capacitor
Principle of operation:
In silicon capacitive accelerometer first the input acceleration signal is first converted to a
position signal. The position signal is obtained from the inertial mass
spring arrangement. Then
this position signal is measured using a differ
ential capacitor arrangement. Simplified view is
shown in the figure below.
Fig: Simplified view of sensor under acceleration
When the input acceleration signal is applied, due to inertia the mass in the mass-spring
arrangement changes its position. The mass consists of movable plate that is made to change its
position, according to input acceleration, in between fixed plates. This forms the differential
capacitor arrangement. A picture of differential capacitor arrangement is shown below.
Fig: A differential capacitor arrangement and equivalent circuit connection
In a differential capacitor arrangement when the movable plate moves the distance
between one pair of electrodes decreases while the distanc
distancee between other pair increases. As a
result both the capacitances C1 and C2 change. This causes a change in output voltage.
Fabrication details:
Surface micromachining technology is used in the construction of ADXL193
accelerometer device. In this technol
ogy the components are fabricated onto the surface of a
substrate. Structures are fabricated on the surface using selective electroforming. In this
technique a metal is electroplated onto substrate through a patterned photoresist. Suspended
elements like cantilever which forms the movable electrode fixed to mass, is fabricated on the
top of a previously deposited sacrificial layer. After the elements are formed, the sacrificial layer
is removed leaving the sense element or structural layer. In this device polysilicon and silicon
forms the structural layer. Silicon dioxide forms the sacrificial layer. Electrodes are made out of
gold and silicon nitride forms the insulator material. Microscopic view of sensor region is shown
Fig: Sensor region of capacitive accelerometer
Application :
Vibration monitoring and control
Vehicle collision sensing
Shock detection
Submitted By:
Renju Devassy
• Company name
: Freescale Semiconductors
Component name
: MPXV7007 (Piezoresistive pressure sensor )
Cost of product
: ( 6-7) US$
: 10×10×5 mm
: Thermoplastic surface mount packaging(PPS)
Piezoresistive pressure sensors were some of the first MEMS devices to be
commercialized. Compared to capacitive pressure sensors, they are simpler to integrate with
electronics, their response is more linear and they are inherently shielded from RF noise. They
do, however, usually require more power during operation and the fundamental noise limits of
the sensor are higher than their capacitive counterparts. Historically, piezoresistive devices have
been dominant in the pressure sensor market.
The MPXV7007 piezoresistive transducers are state-of-the-art monolithic silicon pressure
sensors designed for a wide range of applications, but particularly those employing a
microcontroller or microprocessor with A/D inputs. This transducer combines advanced
micromachining techniques, thin film metallization, and bipolar processing to provide an
accurate, high level analog output signal that is proportional to the applied pressure. MPXV7007
chip is shown below. The device accepts an input pressure range of -7 kPa to +7 kPa. The output
voltage varies from 0.5V to 4.5V. The cost of the device is `450.
Fig: MPXV7007 CHIP
Sensing principle:
Pieoresistive pressure sensors are one of the very first products of MEMS technology.
Piezoresistivity is the change in electrical resistivity of a semiconductor or metal when
mechanical strain is applied to it. The effect was first discovered by Lord Kelvin in the year
1856. When a strain is applied to conducting and semiconducting materials there is a change in
inter-atomic spacing. This affects the bandgap, making it easier for electrons to be raised into the
conduction band. This results a change in resistivity of the material.
The piezoresistive effect of semiconductor materials can be several orders of magnitudes
larger than the geometrical effect and is present in materials like germanium, polycrystalline
silicon, amorphous silicon, silicon carbide, and single crystal silicon. The piezoresistive effect of
semiconductors has been used for sensor devices. Many commercial devices such as pressure
sensors and acceleration sensors employ the piezoresistive effect in silicon. Piezoresistors are
resistors made from a piezoresistive material and are usually used for measurement of
mechanical stress. They are the simplest form of piezoresistive devices.
Fig: A MEMS Piezoresistor
A MEMS piezoresistor which contains a silicon diaphragm onto which piezoresistors are
mounted is shown in figure above. When the diaphragm experiences a pressure it deflects. This
deflection causes a change in resistivity of the piezoresistors due to the strain experienced by
them. Piezoresistors are mounted on the diaphragm in such a way that it experiences the
maximum strain due to pressure in order to improve the sensitivity of the device.
Principle of operation:
The pressure sensor is realized using four piezoresistors arranged on a membrane in
Wheatstone bridge configuration as shown in figure below. The sensitivity depends on the
orientation of piezoresistor and the location of piezoresistors on the membrane. In MPXV7007
all the piezoresistors are arranged on the surface of silicon membrane in a Wheatstone bridge
format. The arrangement is shown below. In the arrangement under no pressure all the resistors
R1, R2, R3 and R4 experience no strain. Hence all the resistors have the same resistivity. So the
output voltage will be zero as the bridge is balanced.
When a pressure is applied the diaphragm deflects and all the four resistors experience
strain and an equivalent change in resistivity. R1 and R3 experience longitudinal strain where as
R2 and R4 experience transverse strain. Hence the bridge will get unbalanced and there will be
an output voltage. This is the basic working principle of piezoelectric pressure sensor.
Fig: Arrangement of Piezoresistors on diaphragm
Fabrication details:
In MPXV7007 bulk micromachining technology is used to construct Si membrane. Then
onto the membrane piezoresistor patterns are formed using photolithography and oxide etching is
done. Later dopants are diffused to form the piezoresistors. Aluminium is patterned to form the
electrode contacts. Microscopic view of sensor region is shown below.
Fig: Top view of Sensor region
Home appliances: Washing machines, Dishwashers, Vacuum cleaners etc.
Automotive applications: Oil level, Gas level, Air pressure detection.
Biomedical Applications: Blood pressure measurement.
Submitted By:
Athira Manohar
So far we have seen different mems components being adhered to different types of packages.
Packaging description of different MEMS components is as follows.
1). LGA(Land Grid Array): The land grid array is a packaging technology with a square grid
of contacts on the underside of a package. The contacts are to be connected to a grid of contacts
on the PCB. Not all rows and columns of the grid need to be used. The contacts can either be
made by using an LGA socket, or by using solder paste.
LGA packaging is related to ball grid array (BGA) and pin grid array (PGA) packaging. Unlike
pin grid arrays, land grid array packages are designed to fit both in a socket or be soldered down
using surface mount technology. PGA packages cannot be soldered down using surface mount
technology. In contrast with a BGA, land grid array packages in non socketed configurations
have no balls and use a flat contact which is soldered directly to the PCB and BGA packages
have balls as their contacts in between the IC and the PCBs.
The LGA (Land Grid Array) is a type of surface mount packaging for integrated circuits that is
notable for having the pins on the socket rather than the integrated circuits. An LGA can be
electrically connected to a printed circuit board either by the use of socket or by soldering
2).Chip Carrier Packages: In electronics, a chip carrier is one of several kinds of surface
mount technology packages for integrated circuits. Connections are made on all four edges of a
square package; the internal cavity for mounting the integrated circuit is large, compared to the
package overall size. Chip carriers may have either J-shaped metal leads for connections by
solder or by a socket, or may be lead-less with metal pads for connections. If the leads extend
beyond the package, the preferred description is "flat pack". Chip carriers are smaller than dual
in-line packages and since they use all four edges of the package can have a larger pin count.
Chip carriers may be made of ceramic or plastic. Some forms of chip carrier package are
standardized in dimensions and registered with trade industry associations such as JEDEC. Other
forms are proprietary to one or two manufacturers. Sometimes the term "chip carrier" is used to
refer generically to any package for an integrated circuit.
Types of chip-carrier package are usually referred to by initialisms and include:
BCC: Bump Chip Carrier
CLCC: Ceramic Leadless Chip Carrier
Leadless chip carrier (LCC): Leadless Chip Carrier, contacts are recessed vertically.
LCC: Leaded Chip Carrier
LCCC: Leaded Ceramic Chip Carrier
DLCC: Dual Lead-Less Chip Carrier (Ceramic)
PLCC: Plastic Leaded Chip Carrier
3)Chip Scale Package: A chip scale package or chip-scale package (CSP) is a type
of integrated circuit package. Originally, CSP was the acronym for chip-size packaging. Since
only a few packages are chip size, the meaning of the acronym was adapted to chip-scale
packaging. According to IPC’s standard J-STD-012, Implementation of Flip Chip and Chip
Scale Technology, in order to qualify as chip scale, the package must have an area no greater
than 1.2 times that of the die and it must be a single-die, direct surface mountable package.
Another criterion that is often applied to qualify these packages as CSPs is their ball pitch should
be no more than 1 mm. The concept was first proposed by Junichi Kasai of Fujitsu and Gen
Murakami of Hitachi Cable. The first concept demonstration however came from Mitsubishi
The die may be mounted on an interposer upon which pads or balls are formed, like with flip
chip ball grid array (BGA) packaging, or the pads may be etched or printed directly onto
the silicon wafer, resulting in a package very close to the size of the silicon die: such a package is
called a wafer-level package (WLP) or a wafer-level chip-scale package (WL-CSP).
Types of chip scale packages:
Chip scale packages can be classified into the following groups:
1. Customized lead frame-based CSP (LFCSP)
2. Flexible substrate-based CSP
3. Flip-chip CSP (FCCSP)
4. Rigid substrate-based
based CSP
5. Wafer-level
level redistribution CSP (WL
4)Quad Flat No-Leads:
QFN cross-sectional view
The above figure shows the cross section of a Flat N
o lead package with a lead frame and wire
bonding. There are two types of body designs,
designs,punch singulation and saw singulation.
singulation Saw
singulation cuts a large set of packages in parts. In punch singulation, a single package is
moulded into shape. The cross sec
section shows a saw-singulated
singulated body with an attached thermal
head pad. The lead frame is made of copper alloy and a thermally conductive adhesive is used
for attaching the silicon die to the thermal pad. The silicon die is electrically connected to the
lead frame by 1-2 mil diameter gold wires.
The pads of a saw singulated package can either be completely under the package, or they can
fold around the edge of the package.
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