SM5852-008-D-3-N中文资料
SILICON
MICROSTRUCTURES I N C O R P O R A T E D
SM5812/SM5852
Amplified Pressure Sensor
? N OW WITH ACCESS TO D IGITAL T EMPERATURE AND C ORRECTED D IGITAL P RESSURE ? L OW -COST , FULLY AMPLIFIED , CALIBRATED , AND COMPENSATED IN A SINGLE PACKAGE
? A VAILABLE FOR D IFFERENTIAL , S INGLE -ENDED DIFFERENTIAL , G AGE & A BSOLUTE APPLICATIONS ?
M ULTIPLE 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 micro-controller 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
pressure available through I 2
C interface ? Output ratiometric with supply voltage ? Multi-order correction for pressure non-linearity (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
TYPICAL APPLICATIONS
? Barometric measurement ? Medical instrumentation ? Pneumatic control ? Gas flow
? Respirators and ventilators
?
Heating, Ventilation and Air Conditioning (HVAC)
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
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
accessible through an I 2
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.
Analog Output
SDA SCL
SILICON
MICROSTRUCTURES I N C O R P O R A T E D
SM5812/SM5852
CHARACTERISTICS FOR SM5812/SM5852 – SPECIFICATIONS
All parameters are measured at room temperature while applying 5.000V supply, unless otherwise specified.
Absolute 1, Gage & Single 2
Differential
MIN TYP MAX MIN TYP MAX UNITS NOTES Zero output (absolute and gauge) 0.42 0.50 0.58 V 3 Zero output (differential)
2.42
2.50
2.58
V
3
Output Span
3.92
4.00 4.08 1.96 2.00 2.04 V FS 3, 4
0.15 PSI 3.80 4.00 4.20 1.90 2.00 2.10 V FS 3, 4 Linearity -0.5 +0.5 -0.5 +0.5 %FS 5 0.15 PSI
-2.5
+2.5
-2.5
+2.5
%FS
5 Pressure hysteresis 5812 -0.1 +0.1 -0.1 +0.1 %FS
5852 -0.3
+0.3 -0.3 +0.3 %FS Temperature coefficient - Zero
-1.0 +1.0 -1.0 +1.0 %FS 0.15 PSI
-2.5 +2.5 -2.5 +2.5 %FS Temperature coefficient – Span
-1.0 +1.0 -1.0 +1.0 %FS 0.15 PSI
-2.0 +2.0 -2.0 +2.0 %FS Thermal hysteresis -0.1 +0.1 -0.1 +0.1 %FS Response Time 2 2 msec Supply voltage 4.75 5.00 5.25 4.75 5.00 5.25 V 3, 7
Current consumption
10 10 mA
Overpressure 5812 3X 3X %FS 6
5852 15X
15X %FS 6 Operating temperature range -40 25 +125 -40 25 +125 °C Compensated temperature range 0 25 +70 0 25 +70 °C
Storage temperature range -55
25
+135
-55
25
+135
°C
Media compatibility 8
Weight 3 3 gram
Notes: 1. Absolute parts are only offered in the SM5812 Series.
2. Single-ended parts (Pressure Type - S) have 2 ports and are for higher gain differential applications where the differential pressure is always positive.
3. Sensor output is ratiometric to supply.
4.
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 full-scale is 4.5 volts to give a span of ±2.0 V.
5. Defined as best fit straight line for positive pressure applied to the part
6. 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.
7. A 100 nF filter capacitor must be placed between Vsupply and Ground.
8.
Clean, dry gas compatible with wetted materials. Wetted materials include Pyrex glass, silicon, alumina ceramic, epoxy, RTV, gold, aluminum, and nickel.
SM5812/SM5852
ADDITIONAL INFORMATION
Full-Scale Pressure Ranges
SM5812 PSI [kPa] SM5852 PSI [kPa]
005 5 [34.5] 001 0.15 [1.0] 015 15 [103.4]
003 0.30 [2.1] 030 30 [206.8]008 0.80 [5.5] 060 60 [413.7]015 1.50 [10.3] 100 100[689.5]
030 3.00 [20.7]