SILICON MICROSTRUCTURES INCORPORATED
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SM5812/SM5852 Amplified Pressure Sensor
NOW WITH ACCESS TO DIGITAL TEMPERATURE AND CORRECTED DIGITAL PRESSURE LOW-COST, FULLY AMPLIFIED, CALIBRATED, AND COMPENSATED IN A SINGLE PACKAGE AVAILABLE FOR DIFFERENTIAL, SINGLE-ENDED DIFFERENTIAL, GAGE & ABSOLUTE APPLICATIONS MULTIPLE PRESSURE RANGES AVAILABLE TO MEASURE PRESSURE DOWN TO 0.15 PSI FULL-SCALE
AND UP TO 100
PSI FULL-SCALE
DESCRIPTION
The Silicon Microstructures SM5812 and SM5852 series of OEM pressure sensors combines state-of-the-art pressure sensor technology with CMOS digital signal processing technology to produce an amplified, fully conditioned, multi-order pressure and temperature compensated sensor in a dual in-line package (DIP) configuration. Combining the pressure sensor with a custom signal conditioning ASIC in a single package simplifies the use of advanced silicon micromachined pressure sensors. Now, the pressure sensor can be mounted directly to a standard printed circuit board and an amplified, high level, calibrated pressure signal can be acquired from the digital interface or analog output. This eliminates the need of additional circuitry, such as a compensation network or microcontroller containing a custom correction algorithm. The SM5812/SM5852 Series pressure sensors are based on SMI's highly stable, piezoresistive pressure sensor chips mounted on a ceramic substrate. An electronically programmable ASIC is contained in the same package to provide calibration and temperature compensation. The model SM5812 is designed for operating pressure ranges from 0-5 PSI up to 0-100 PSI. The model SM5852 is designed for operating pressure ranges from 0-0.15 PSI up to 0-3 PSI. For both models, the sensor output is ratiometric with the supply voltage.
FEATURES
• • • • • • • Amplified, calibrated, fully signal conditioned output span of 4.0 VDC FS (0.5 to 4.5 V signal) Digital temperature and calibrated 2 pressure available through I C interface Output ratiometric with supply voltage Multi-order correction for pressure nonlinearity (factory programmed) Multi-order correction for temperature coefficient of span and offset (factory programmed) Gage, differential, and absolute versions SMI’s unique low-pressure die allows for a full-scale pressure range of 0-0.15 PSI Barometric measurement Medical instrumentation Pneumatic control Gas flow Respirators and ventilators Heating, Ventilation and Air Conditioning (HVAC)
TYPICAL APPLICATIONS
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Rev 1.4 6_05 2005 SMI
Silicon Microstructures, Inc. ♦ 1701 McCarthy Blvd. ♦ Milpitas, CA 95035 ♦ USA Tel: 408-577-0100 ♦ Fax: 408-577-0123 ♦ Sales@si-micro.com ♦ www.si-micro.com
SM5812/SM5852
THEORY OF OPERATION
The operation of the signal processor is depicted in the block diagram below. The external pressure sensor is a piezoresistive bridge. This transduces the applied pressure into an electronic signal, which is then inputted into the integrating amplifier of the ASIC. During the amplification step an offset correction factor is added in order to allow maximum gain for a given pressure while minimizing the offset error. The signal is then passed to an 11-bit analog to digital converter (ADC). The ADC samples the signal multiple times and uses the sum of those samples as a 13-bit word. A digital signal processor (DSP) is then used to correct and calibrate the pressure signal. The DSP provides multi-order correction of both pressure and temperature non-linearity through the use of factory-programmed coefficients. A combined total of twenty
SMI Multi-Order Pressure and Temperature Correction ASIC
coefficients are available for correcting pressure and temperature non-linearity. The unique coefficients are determined during a calibration process performed at the factory. Factory calibration is the last step performed which means the effect of the package on the pressure signal will also be taken into account. This provides a great advantage over conventional laser-trimming approaches. The DSP outputs a corrected digital word, which travels to a 12-bit digital to analog converter (DAC) to provide a calibrated analog output. In addition to the analog output, the corrected pressure signal is 2 accessible through an I C digital interface. See SMI application note AN05-001 for a detailed description of how to read out the digital corrected pressure signal using the I2C bus interface.
+ 5 VDC
+ 5 VDC
Band-gap External Piezoresistive Bridge
VTemp DSP (multi-order correction of pressure and temperature nonlinearities)
Ground
Switched Capacitor Integrateing Amplifier
MUX
11-bit ADC
12-bit SigmaDelta DAC
Power-On Reset
Analog Timing Control
EEPROM Array
Output Buffer
Analog Output
2 MHz Oscillator
Digital Timing and Control Management
I2C Digital Interface
SDA SCL
Analog Component
Ground
Digital Component
Rev 1.4 6_05 2005 SMI
Silicon Microstructures, Inc. ♦ 1701 McCarthy Blvd. ♦ Milpitas, CA 95035 ♦ USA Tel: 408-577-0100 ♦ Fax: 408-577-0123 ♦ Sales@si-micro.com ♦ www.si-micro.com
SILICON MICROSTRUCTURES INCORPORATED
SM5812/SM5852
CHARACTERISTICS FOR SM5812/SM5852 – SPECIFICATIONS
All parameters are measured at room temperature while applying 5.000V supply, unless otherwise specified. Absolute , Gage & Single
MIN Zero output (absolute and gauge) Zero output (differential) Output Span 0.15 PSI Linearity 0.15 PSI Pressure hysteresis 5812 5852 Temperature coefficient - Zero 0.15 PSI Temperature coefficient – Span 0.15 PSI Thermal hysteresis Response Time Supply voltage Current consumption Overpressure Operating temperature range Compensated temperature range Storage temperature range Media compatibility Weight Notes: 1. 2. 3. 4. Absolute parts are only offered in the SM5812 Series. Single-ended parts (Pressure Type - S) have 2 ports and are for higher gain differential applications where the differential pressure is always positive. Sensor output is ratiometric to supply. Full-scale (FS) is defined as zero pressure to rated pressure; differential parts can be used ±FS. Absolute and Gauge zero output is 0.5 V typical and full-scale output is 4.5 V. Span is the difference between Full-scale output and zero output, (4 V). For Differential parts, the negative full-scale is typically at 0.5 V, zero is typically 2.5 V, and positive fullscale is 4.5 volts to give a span of ±2.0 V. Defined as best fit straight line for positive pressure applied to the part Or 225 PSI, whichever is less. Output amplifier will saturate at about 0.25 V for applied pressure below the rated Zero and at about 4.75 V for applied pressure above the rated Full-scale. A 100 nF filter capacitor must be placed between Vsupply and Ground. Clean, dry gas compatible with wetted materials. Wetted materials include Pyrex glass, silicon, alumina ceramic, epoxy, RTV, gold, aluminum, and nickel. 3 3 gram 5812 5852 3X 15X -40 0 -55 25 25 25 +125 +70 +135 3.92 3.80 -0.5 -2.5 -0.1 -0.3 -1.0 -2.5 -1.0 -2.0 -0.1 2 4.75 5.00 5.25 10 3X 15X -40 0 -55 25 25 25 +125 +70 +135 4.00 4.00 4.08 4.20 +0.5 +2.5 +0.1 +0.3 +1.0 +2.5 +1.0 +2.0 +0.1 0.42 TYP 0.50 M AX 0.58 2.42 1.96 1.90 -0.5 -2.5 -0.1 -0.3 -1.0 -2.5 -1.0 -2.0 -0.1 2 4.75 5.00 5.25 10 2.50 2.00 2.00 2.58 2.04 2.10 +0.5 +2.5 +0.1 +0.3 +1.0 +2.5 +1.0 +2.0 +0.1
1 2
Differential
MIN TYP M AX UNITS V V V FS V FS %FS %FS %FS %FS %FS %FS %FS %FS %FS msec V mA %FS %FS °C °C °C 8 6 6 3, 7 NOTES 3 3 3, 4 3, 4 5 5
5. 6. 7. 8.
Rev 1.4 6_05 2005 SMI
Silicon Microstructures, Inc. ♦ 1701 McCarthy Blvd. ♦ Milpitas, CA 95035 ♦ USA Tel: 408-577-0100 ♦ Fax: 408-577-0123 ♦ Sales@si-micro.com ♦ www.si-micro.com
SM5812/SM5852
ADDITIONAL INFORMATION
Package Dimensions & Pin-Out
Dual Inline Pin (DIP) Option Pin Numbers (for both DIP & Surface Mount)
PIN 1 2 3 4 5 6 7 8
DESCRIPTION NC GROUND NC SERIAL DATA (SDA) SERIAL CLOCK (SCL) NC Vexc = 5.000 VDC ANALOG OUTPUT
NOTES: • Do not connect to NC pins. • External connections to NC pins will cause part malfunction. • All dimensions are shown in inches. • Tolerance on all dimensions +0.005” unless otherwise specified.
Surface Mountable Pin Option
Ordering Information
Pin Configuration 3 : DIP pins, opposite direction of tubes 5 : Surface mountable pins, Model Number opposite direction of tubes Tube Length L : Long (0.480" ± 0.005") N : No tube Pressure Type A : Absolute (1 port) D : Differential (2 ports) G : Gauge (1 port) S : Single-ended (2 ports)
Full-Scale Pressure Ranges
SM5812
Pin Configuration
PSI 5 15 30 60
[kPa] [34.5] [103.4] [206.8] [413.7]
SM5852 001 003 008 015 030
PSI 0.15 0.30 0.80 1.50 3.00
[kPa] [1.0] [2.1] [5.5] [10.3] [20.7]
005 015 030 060 100
SM5852 - 003 - D - 3 - L
Pressure Range Pressure Type Tube Length
100 [689.5]
Notes 1. Absolute configuration only available in SM5822. 2. Single-ended configuration is for higher gain differential applications where differential pressure is always positive. 3. Other configurations available on large orders. Consult SMI for details.
Wiring Diagrams
Vexc = + 5.000 VDC ANALOG OUTPUT
Vexc = + 5.000 VDC SERIAL CLOCK (SCL)
SERIAL DATA (SDA)
SM5812/SM5852
100 nF
100 nF
SM5812/SM5852
GROUND
GROUND
GROUND
GROUND
Wiring diagram for analog output
Notice:
Wiring diagram for digital output
Silicon Microstructures, Inc. reserves the right to make changes to the product contained in this publication. Silicon Microstructures, Inc. assumes no responsibility for the use of any circuits described herein, conveys no license under any patent or other right, and makes no representation that the circuits are free of patent infringement. While the information in this publication has been checked, no responsibility, however, is assumed for inaccuracies. Silicon Microstructures, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of a life-support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications.
Rev 1.4 6_05 2005 SMI
Silicon Microstructures, Inc. ♦ 1701 McCarthy Blvd. ♦ Milpitas, CA 95035 ♦ USA Tel: 408-577-0100 ♦ Fax: 408-577-0123 ♦ Sales@si-micro.com ♦ www.si-micro.com