SM5812
Amplified Pressure Sensor
•
•
•
•
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.
Rev 1.5 7_07
©
2005 - 2007
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
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 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
Amplified Pressure Sensor
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
SMI Multi-Order Pressure and
Temperature Correction ASIC
+ 5 VDC
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
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
Band-gap
External
Piezoresistive
Bridge
V
Temp
DSP
(multi-order
correction of
pressure and
temperature
non-
linearities)
Ground
Switched
Capacitor
Integrateing
Amplifier
MUX
11-bit ADC
12-bit
Sigma-
Delta DAC
Power-On
Reset
Analog
Timing
Control
EEPROM
Array
Output
Buffer
Analog
Output
2 MHz
Oscillator
Digital Timing
and Control
Management
I
2
C Digital
Interface
SDA
SCL
Analog Component
Ground
Digital Component
Rev 1.5 7_07
©
2005 - 2007
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
Amplified Pressure Sensor
CHARACTERISTICS FOR SM5812 –
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
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
MAX
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
MAX
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
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.
Rev 1.5 7_07
©
2005 - 2007
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
Amplified Pressure Sensor
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
V
exc
= 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
Full-Scale Pressure Ranges
SM5812
005
015
030
060
100
PSI
5
15
30
60
[kPa]
[34.5]
[103.4]
[206.8]
[413.7]
100 [689.5]
Wiring Diagrams
V
exc
= + 5.000 VDC
ANALOG OUTPUT
V
exc
= + 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
Wiring diagram for digital output
Rev 1.5 7_07
©
2005 - 2007
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
Amplified Pressure Sensor
NOTICE
Information in this document is provided solely to enable software and system implementers to use Silicon
Microstructures, Inc. products and/or services. No express or implied copyright licenses are granted hereunder to design
or fabricate any silicon-based microstructures based on the information in this document.
Silicon Microstructures, Inc. makes no warranty, representation, or guarantee regarding the suitability of its products for
any particular purpose, nor does Silicon Microstructures, Inc. assume any liability arising out of the application or use of
any product or silicon-based microstructure, and specifically disclaims any and all liability, including without limitation
consequential or incidental damages. Parameters that may be provided in Silicon Microstructures, Inc. data sheets and/or
specifications can and do vary in different applications and actual performance may vary over time. Silicon
Microstructures, Inc. assumes no responsibility for any inaccuracies and/or errors in this publication. All operating
parameters, must be validated for each customer application by customer’s technical experts. Silicon Microstructures,
Inc. does not convey any license under its patent rights nor the rights of others. Silicon Microstructures, Inc. makes no
representation that the circuits are free of patent infringement. Silicon Microstructures, Inc. products are not designed,
intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications
intended to support or sustain life, or for any other application in which the failure of the Silicon Microstructures, Inc.
product could create a situation where personal injury or death may occur. Should Buyer purchase or use Silicon
Microstructures products for any such unintended or unauthorized application, Buyer shall indemnify and hold Silicon
Microstructures, Inc. and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs,
damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or
death associated with such unintended or unauthorized use, even if such claim alleges that Silicon Microstructures, Inc.
was negligent regarding the design or manufacture of the part. Silicon Microstructures, Inc. reserves the right to make
changes without further notice to any products herein
Silicon Microstructures, Inc.
TM
and the Silicon Microstructures, Inc. logo are trademarks of Silicon Microstructures, Inc. All
other service or product names are the property of their respective owners.
© Silicon Microstructures, Inc. 2001-2007. All rights reserved.
Rev 1.4 6_07
Rev 1.5 7_07
©
2005 - 2007
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
