Low Pressure Sensing Chip uses Advanced MEMS Technology
July 7, 2010 by admin
Filed under Frank Talk
Welcome to Frank Talk about Sensors. I’m Randy Frank and today I’m talking to Tim Shotter, director of new products at All Sensors, a leading supplier of MEMS-based pressure sensors and systems. Tim, welcome back to Frank Talk About Sensors.
MEMS Piezoresistive Low Pressure Sensing Die
May 5, 2010 by Randy Frank
Filed under Featured, Pressure
Morgan Hill, CA – All Sensors Corporation announces the introduction of a low pressure sensor die for high volume applications requiring pressure measurement to as low as a quarter inch of water full scale. This introduction of a new pressure sensor die marks the fifth major silicon pressure sensor die topology to be introduced over the past fifty years.
Die Features
The MEMS Piezoresistive Low Pressure Sensing Die utilizes an open bridge configuration, measuring 2mm x 2mm square. Industry best sensitivity specifications are made possible by break though process technology in combination with innovative MEMS topology. The new die design features maximum pressure response while maintaining low package stress susceptibility. By utilizing a boss-less structure the position sensitivity is minimized (typically 0.1% inH2O/g).
History
In the 1960′s Bell Labs developed and Honeywell commercialized the first silicon pressure sensor using longitudinal and transverse strain sensitive resistors with square micromachined diaphragms. This design provided acceptable performance to as low as one psi.
In the 1970′s Motorola introduced a shear strain silicon pressure sensor with performance targeted for automotive manifold absolute pressure (MAP) applications. These sensors incorporate shear strain sensitive resistors with square micromachined diaphragms with superior performance at 15 psia.
Also, in the 1970′s several companies developed and commercialized silicon variable capacitance structures designed to detect either parallel plate changes in capacitance with pressure or changes in edge effect variable capacitance with changes in pressure. These sensors provided excellent response to pressures less than one inch of water. These sensors where either too large or too expensive for many applications.
In the 1980′s several companies, most notably Silicon Microstructures, introduced longitudinal and transverse strain sensors with enhanced silicon microstructures to provide excellent pressure sensing to as low as several inches of water. Honeywell and others have been able to use this structure in conjunction with Honeywell patent 6,023,978 to extend the range to below an inch of water full scale.
This year All Sensors has developed, introduced and will commercialize a next generation silicon pressure sensor that provides superior performance to fractions of an inch of water full scale. This sensor combines elements of features found in pressure sensors dating back to bonded strain gage sensors of the 1950′s to enhanced, state of the art, silicon micromachining of silicon on insulator (SOI) wafers.
All Sensors
www.allsensors.com
Millivolt Low Voltage Pressure Sensors from All Sensors
Morgan Hill, CA - All Sensors Corporation has announced a new line of Millivolt Low Voltage Pressure Sensors. The new Millivolt Low Voltage Pressure Sensors (MLV Series) are based upon All Sensors’ CoBeam2™ Technology. CoBeam2™ Technology helps reduce package stress as well as greatly improves position sensitivity when compared with competitive sensors. The MLV Series device has a temperature compensated output signal and is calibrated for zero and span. By offering a compensated and calibrate output signal, many errors associated with pressure measurement are corrected, offering an accurate and stable signal. The MLV Series device provides a high output signal at a low operating voltage. This is the result of an extremely sensitive sensing element capable of operating at low supply voltages. Lower operating voltages result in improved errors due to warm-up shift. The MLV Series afford design engineers a new compensated millivolt pressure sensor capable of low pressure measurement with improved energy efficiency. The Millivolt Low Voltage (MLV) Series is available in 1, 5, 10, 20, and 30 inH2O pressure ranges.
The MLV Series is offered in a pc board mountable package. Several packages and port configurations are available including gage and differential devices. The MLV Series employs All Sensors’ CoBeam2 TM Technology. The device provides a compensated and calibrated mV output signal. The MLV Series device is specified at 5 volt excitation with just over 2mW power consumption.
Ideal applications for this device are; portable devices, battery operated devices, medical breathing, medical devices associated with low pressure, remote sensing, HVAC, and industrial controls.
All Sensors Corporation
www.allsensors.com
Basic Low Voltage Pressure Sensors from All Sensors
Morgan Hill, CA — All Sensors Corporation announces a new line of Basic Low Voltage Pressure Sensors. The new Basic Low Voltage Pressure Sensor product family consists of two product series, the Basic Low Voltage (BLV) Series and the Basic Low Voltage Reference (BLVR) Series. Both the BLV and BLVR are based upon All Sensors’ CoBeam2 TM Technology. CoBeam2 TM Technology helps reduce package stress as well as greatly improves position sensitivity when compared with competitive sensors. The BLV Series device utilizes a single die technology while the BLVR Series utilizes a dual die reference technology to reduce all output offset or common mode errors. The BLV and BLVR Series devices provide a high output signal at a low operating voltage. This is the result of an extremely sensitive sensing element capable of operating at low supply voltages. Lower operating voltages result in improved errors due to warm-up shift. The BLV and BLVR afford design engineers a new basic pressure sensor capable of low pressure measurement with improved energy efficiency. The Basic Low Voltage (BLV) Series is available in 1, 5, 10, 20, and 30 inH2O pressure ranges. The Basic Low Voltage Reference (BLVR) Series is also available 1, 5, 10, 20, and 30 inH2O pressure ranges.
The sensors are offered in a pc board mountable package. Multiple port configurations are available including gage and differential devices.
The BLV and BLVR employ All Sensors’ CoBeam2 TM Technology. Both devices provide a basic, uncompensated mV output. The BLVR Series device employs a dual die reference technology to reduce all output offset or common mode errors. The BLV Series device is specified at 1.8 volt excitation with 1mW power consumption. The BLVR (dual die) is specified at 3.3 volt excitation with 7 mW power consumption. Low operating voltage offers increased energy efficiency.
All Sensors
www.allsensors.com
Pressure Sensor Provides Full Scale Millivolt Output
Morgan Hill, CA – All Sensors Corporation announces the release of a ½ inH2O Full Scale Millivolt Output Pressure Sensor. This announcement marks the first ½ inH2O Millivolt Output Pressure Sensor released to the market. Obtaining a ½ inch measurement from a millivolt device has become possible utilizing proprietary All Sensors’ CoBeam2™ Technology. The ½ inch device is an addition to the existing family of 1 to 30 inH2O Millivolt Output Pressure Sensors. The ½ inch device offers 2x the sensitivity of the 1 inH2O device which provides higher signal to noise for the most demanding low pressure applications. For the first time customers can now obtain ½ inch pressure measurements from a millivolt output device. This pressure range has traditionally only been available as an amplified device. This millivolt pressure sensor offers accurate, low pressure measurements at a more affordable price point. The entire ½ to 30 inH2O pressure sensor family is RoHS compliant.
Package Features The sensors are offered in a pc board mountable package with two pressure ports. Seven pressure ranges are available from ½ inH2O full scale to 30 inH2O full scale. The dead volume to each pressure port is matched for superior common mode response.
Electrical Features The sensors are available with a millivolt output proportional to either gage or differential pressure. Output offset errors are significantly reduced by electrical cross coupling compensation employed within the sensor. Position sensitivity is virtually immeasurable by utilizing proprietary All Sensors’ CoBeam2™ Technology.
Applications Ideal applications for this device are medical breathing (Lung function, Respiratory monitory, Sleep diagnostics, and Drug delivery systems), HVAC, and process automation.
Price Contact factory for price. Samples are available for product testing.
Accuracy vs. Resolution
Purpose: To describe the difference between “accuracy” and “resolution” for silicon based pressure sensors.
Application: Any application.
Discussion: Silicon based pressure sensor inherently have infinite resolution. The limit to the practical use of this limitless resolution is based upon many factors associated with the compensation and amplification of the output signal and the accuracy demanded by the application.
All the figures show an output signal where the output of the sensor is displayed as a signal quantized (stepped) by an analog to digital converter after some amplification of the pressure sensor signal. For ease of display the steps are relative to each other and not representative of a typical system. For instance a relatively low accuracy system would be an 8-bit system resulting in quantization of the signal into 256 steps (28). As a practical matter for today’s sensors and added electronics the limit to the resolution with accuracy acceptable to most applications is roughly one part in sixty thousand, or a 16-bit system (216). For such a system the analog to digital converter would be somewhere between 18-bits to 24-bits.
All Sensors
www.allsensors.com
Surface Mount Basic Pressure Sensor
Morgan Hill, CA – Surface mount basic pressure sensors from All Sensors Corporation offer an unprecedented 10-INCH H2O pressure range and are also available with virtually zero position sensitivity. The Surface Mount Basic Pressure Sensor is RoHS compliant.
Package Features
The Surface Mount Basic Pressure Sensor is available as a gage or absolute pressure sensor. Packages can be configured with a ported lid or a non-ported lid. The footprint of the device measures 0.3” x 0.3”. The Surface Mount Basic Pressure Sensor is packaged as an 8-pad leadless chip carrier.
Electrical Features
The Surface Mount Basic Pressure Sensor is available as a gage device with pressure ranges of 10 INCH H2O, 5 PSI, 15 PSI, 30 PSI, and 100 PSI, as well as an absolute pressure device with a range of 15 PSI. The output is ratiometric to the supply voltage and proportional to the applied pressure.
