Datasheet SDP1108-R
Low Differential Pressure Sensor
with fast response time
− For medical ventilators (ICU and home care)
− High sensitivity below 10 Pa to measure small volume flow (neonatal)
− Fast response time for efficient trigger function
− Unsurpassed performance thanks to CMOSens® technology
− Offset and hysteresis free
− Fully calibrated and temperature compensated
− Not sensitive to the mounting orientation and vibrations
SDP1108-R Product Summary
The SDP1108-R sensor is a differential pressure sensor
for air based on the successful SDP1000 sensor from
Sensirion. The response time of the SDP1108-R has
been optimized for medical ventilation applications.
Mounted in a rugged, chemically inert PPS housing the
SDP1108-R differential pressure sensors feature a unique
dynamic range, zero offset and unsurpassed long term
stability. This makes it an ideal fit for demanding yet cost
sensitive OEM applications in medical and HVAC
equipment.
The SDP1108-R is supplied with 5.0 V and provides a
0.25…4.0 V output. Although the output of the sensor is
analog, the internal linearization and temperature
compensation is performed digitally. This results in a
Its leading performance is based on Sensirion’s proprietary
CMOSens® sensor technology which combines the sensor
element with amplification and A/D conversion on one
single silicon chip. The differential pressure is measured by
a thermal sensing element. In contrast to other thermal
differential pressure sensors only a very small amount of
air is required. This leads to a reliable operation even
under harsh conditions. In comparison to membrane and
piezo-resistive based sensors the SDP1108-R differential
pressure sensors show an extended measurement range,
better offset stability and improved reproducibility even at
lowest pressure ranges. In addition the SDP1108-R is
robust against pressure bursts and shows no sensitivity to
the mounting orientation.
www.sensirion.com
Version 2.1 – November 2016
DIGITAL
Linearization and
Temperature
compensation
Differential
pressure
Sensor
CMOSens®
SENSOR CHIP
D/A
converter
Medical applications:
Homecare ventilation
Intensive care ventilation (ICU)
Memory
Block Diagram
A/D converter
Applications
superior accuracy, outstanding resolution (up to 0.05 Pa),
and lowest temperature dependence.
Pin 3: OUT
0.25 V to 4 V
Pin 2:
GND
Pin 1:
VDD 5.0 V
1/7
1
Sensor Output Characteristics1
SDP1108-R
The SDP1108-R provides a fully calibrated voltage
output. To enhance the sensitivity at very low
differential pressures, the SDP1108-R comes with a
root-square output characteristic.
output voltage [V]
3.75
3.25
2.75
2.25
1.75
1.25
0.75
0.25
0
20
40
60
80
100
differential pressure [% FS]
Output _ Voltage 0.25V
Diff. Press.[ Pa ]
500
3.75V
2
1Calibration conditions apply unless
2
Use this formula to convert the sensor output into
physical value.
otherwise noted: 23°C and pabsolute = 966 mbar, dry air, VDD = 5.000 V.
Specifications
Table 1: SDP1108-R Sensor specifications1
SDP1108-R
Parameter
Min
Typ
Max
0.25
-
4
Volts
0
-
500
Pa
0
-
2
Inch water
20% FS to 100% FS
-
1.0
2.0
% Measured Value4
0 to 20% FS
-
zero2
-
100 to 500 Pa
-
0.2
15
0.01
0.3
0.4
40
0.06
1.0
% Full Span5
mV
Pa
% Measured Value
0 to 100 Pa
-
0.05
0.2
% Full Span5
-
0
0.1
Pa / year
0 to 100 % FS
-
0.03
0.05
% Measured Value4 / °C
zero
-
1
2
mV/°C
6.6
8.0
10.1
ms
17
20
24
Hz
Measurement range
Accuracy3
Repeatability
Null drift per year6
Additional error over
temperature7 (T ≠ 23°C)
Response
Unit
time(8)
Cut off frequency of internal filter
1 Calibration conditions apply
unless otherwise noted: 23°C and pabsolute = 966 mbar, dry air, VDD = 5.000 V
between the zero point (offset) of different sensors measured under the same conditions (e.g. same supply voltage, temperature, …)
3 Include deviations due to linearity, hysteresis, and repeatability
4 % Measured value = (SDP1108-R output [Pa] - output of reference instrument [Pa]) / output of reference instrument [Pa].
5 Full span is defined as 3750 mV / 500 Pa for SDP1108-R
6 Drift over time due to aging, pressure cycles… Test results can be provided.
7 The additional error due to temperature variation is temporary. Once the sensor is back to the calibration temperature, the shift disappears
(no hysteresis).
8 Tau= 0 to 63%, filter response time = 8ms.
2 Variance
www.sensirion.com
Version 2.1- August 2016
2/7
Table 2: Additional sensor specifications.
Parameter
Media Calibration1
Air, N2 – for other gases contact Sensirion AG.
Media Compatibility
Operating Conditions2:
- Temperature
- Humidity
Ambient storage conditions3
Air, N2, O2
Orientation sensitivity
below zero point accuracy
Admissible overpressure (short term)
1 bar (14.5 PSI)
Burst Pressure Capability
2 bar (29 PSI)
Weight
14 g
Protection Class
IP 20
Wetted materials
Glass (silicon nitride, silicon oxide), Silicon, PPS (Polyphenylene Sulfide),
PEEK (Polyetheretherketone), FR4, Silicone as static sealing, Epoxy, Gold
Electromagnetic compatibility
EN 61000-4-2
Lead free
Reach and RoHS compliant.
1 Sensors
Air discharge (ESD)
2 kV
are calibrated for a specific gas, please contact Sensirion when you employ different gases than the specified.
2Condensation
3For
-10 °C … +60 °C / 14°F … 140 °F
non-condensing
-40 °C … +80 °C / -40°F … 176 °F
of liquids or dust on the sensor membrane might lead to sensor offset.
maximum 2 weeks
2.1 Temperature Compensation
This leads to the following correction factors:
The SDP1108-R differential pressure sensor features a
sophisticated built-in temperature compensation circuit.
The temperature is measured on the CMOSens® chip by
means of a PTAT bandgap reference temperature
sensor. Its data is fed into a compensation circuit which
is also integrated on the CMOSens® sensor chip. No
external temperature compensation is therefore required.
2.2 Altitude Correction
The SDP1108-R differential pressure sensor achieves its
unsurpassed performance by using a dynamic
measurement principle: An applied differential pressure
forces a small air flow through the SDP1108-R, which
measures this air flow.
The sensor signal is dependent on the ambient air
density. The temperature effect on density is
compensated by internal intelligence (see Paragraph
2.1). Effects on density due to a change of ambient
pressure, typically a change of altitude above sea level,
can be compensated using a correction factor according
to the following equation:
Dpeff = Dpsensor * Pcal / Pamb
Where Dpeff is the effective differential pressure, Dpsensor
the differential pressure indicated by the SDP1108-R, Pcal
the absolute pressure during calibration (966 mbar) and
Pamb the actual ambient absolute pressure.
www.sensirion.com
Table 3: Altitude correction factors.
Altitude
[meter]
0
250
425
500
750
1500
2250
3000
Ambient Pressure
(Pamb) [mbar]
1013
984
966
958
925
842
766
697
Correction Factor
Pcal / Pamb
0.95
0.98
1.00
1.01
1.04
1.15
1.26
1.38
Example:
The SDP1108-R is used at 750 m above sea level.
The output of the SDP1108-R shows 0.5 V, which
corresponds to Dpsensor = 33.3 Pa. Taking into account
the correction factor Pcal / Pamb = 1.04 the effective
differential pressure Dpeff is 33.3 Pa * 1.04 = 34.6 Pa.
Note:
In many medical and HVAC applications such as filter
monitoring, fan/ventilator control or air flow
measurement the described effect is actually
welcome since at the end the mass flow and not
volume flow is the effective value to control.
Version 2.1 – November 2016
3/7
3
Physical Dimensions and Mounting Information
3.1 Housing
The SDP1108-R differential pressure sensor is mounted
in chemically inert PPS housing. The rugged package
has been designed to withstand continuous
overpressures of at least 1 bar (14.5 PSI). Burst pressure
is > 2 bar (29 PSI)
The physical dimensions and mounting information is
given in Figure 1 and 2.
5.2
(0.205)
30.5
(1.200)
13.1
(0.516)
Pin#
1
2
3
22.1
18.3 (0.870)
(0.720)
Function
VDD (5 Vdc)
Ground
OUT (0.25…4 Vdc)
Figure 1: Pin out and physical dimensions in mm (inch). The
drawing is not to scale.
Dim.
[mm]
[inch]
[mil]
A
3.00
0.118
118
B
C
D
E
F
G
H
I
3.30
1.20
10.20
28.20
2.54
0.60
0.50
22.70
0.130
0.047
0.402
1.110
0.100
0.024
0.020
0.894
130
47
402
1110
100
24
20
894
Figure 2: SDP1108-R PCB footprint. The drawing is
not to scale.
3.2 Soldering Instructions
The SDP1108-R differential pressure sensor can be
wave soldered. Direct reflow soldering is not
recommended since it may affect the accuracy.
www.sensirion.com
If reflow soldering is required Sensirion recommends to
use an SMD connector (e.g. type Samtec SSM-103-LSV) and to mount the SDP1108-R after soldering.
Version 2.1 – November 2016
4/7
3.3 Connecting Hose
Sensirion recommends a hose with an inner diameter
of 3.18 to 3.8mm (1/8 to 3/20 inch). Due to the dynamic
measurement principle, a small air flow is required
(Figure 3) which leads to a dependence on the length
of the hose (Table 4). Tubes up to 1 m show less than
2 % error of the measured value (Table 4).
Table 4: Influence of the length of the connecting hose on
the accuracy (using 4 mm inner diameter). Deviation is
given in % of the measured value. Example SDP1108-R: a
500 Pa difference pressure is shown as 492.5 Pa when
using 1 m tube with 4 mm inner diameter.
Hose length
SDP1108-R
@FS
Figure 3: Typical air flow through the SDP1108-R. Please note:
1 scc/min = 1 cm3/min at 0°C and 1013 mbar pressure
(1 sccm = 0.001 norm liter).
@0.5 FS
0.5 m (20 inch)
-0.75%
-0.95%
1.0 m (40 inch)
-1.5%
-1.9%
2.0 m (80 inch)
-3.0%
-3.8%
Table 5: Maximum flow through the sensor element.
SDP1108-R
Mass flow through sensor element:
4
123 sccm (@ 500 Pa)
Electrical Specifications
4.1 Power Supply
The SDP1108-R differential pressure sensor requires a
stable voltage supply of 5.0 V. The requirements for the
electrical supply are specified in Table 6.
The resistive load at the output pin should be larger
than 20 kOhm. The capacitive load at the output pin
must not be larger than 200 pF. If the design shows a
larger capacity at the output pin an additional resistor is
required in series at the output (e.g. 620 Ohm).
4.2 Voltage Output
The SDP1108-R features a voltage output from 0.25 V
to 4.0 V. An output voltage below 0.25 V indicates a
negative differential pressure (not calibrated).
Table 6: SDP1108-R electrical characteristics.
Parameter
Conditions
Min.
Power Supply Voltage VDD
Operating Current
4.75
5 V, no load, zero flow
Output capacitive load Cload
Recommended load Rload
www.sensirion.com
20
Version 2.1 – November 2016
Typ.
Max.
Units
5.0
5.25
VDC
5.1
6
mA
20
200
pF
100
k
5/7
5
Ordering Information
When ordering please refer to the following part names and article numbers. For the latest product information and
local distributor check out Sensirion’s website on http://www.sensirion.com
Part Name
Article Number
SDP1108-R
1-100339-03
Revision history
Date
Revision
Author
Changes
October 2008
June 2010
V1.0
V1.1
PHA
DAT
February 2013
November 2016
V2
V2.1
ANB
ANB
Initial release
SDP2108 launched, New Item Number (see product change notification PCN
081015), block diagram (page 1), minor changes
Updated product number. Minor layout updates.
SDP2108-R discontinued and removed from datasheet.
www.sensirion.com
Version 2.1 – November 2016
6/7
Important Notices
Warning, personal injury
Do not use this product as safety or emergency stop devices
or in any other application where failure of the product could
result in personal injury (including death). Do not use this
product for applications other than its intended and
authorized use. Before installing, handling, using or servicing
this product, please consult the datasheet and application
notes. Failure to comply with these instructions could result in
death or serious injury.
If the Buyer shall purchase or use SENSIRION products for any
unintended or unauthorized application, Buyer shall defend,
indemnify and hold harmless SENSIRION and its officers,
employees, subsidiaries, affiliates and distributors 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 SENSIRION shall be allegedly negligent with respect to the
design or the manufacture of the product.
ESD Precautions
The inherent design of this component causes it to be sensitive to
electrostatic discharge (ESD). To prevent ESD-induced damage
and/or degradation, take customary and statutory ESD precautions
when handling this product.
See application note “Handling Instructions” for more information.
Warranty
SENSIRION warrants solely to the original purchaser of this
product for a period of 12 months (one year) from the date of
delivery that this product shall be of the quality, material and
workmanship defined in SENSIRION’s published specifications of
the product. Within such period, if proven to be defective,
SENSIRION shall repair and/or replace this product, in
SENSIRION’s discretion, free of charge to the Buyer, provided that:
notice in writing describing the defects shall be given to
SENSIRION within fourteen (14) days after their appearance;
such defects shall be found, to SENSIRION’s reasonable
satisfaction, to have arisen from SENSIRION’s faulty design,
material, or workmanship;
the defective product shall be returned to SENSIRION’s
factory at the Buyer’s expense; and
the warranty period for any repaired or replaced product shall
be limited to the unexpired portion of the original period.
This warranty does not apply to any equipment which has not been
installed and used within the specifications recommended by
SENSIRION for the intended and proper use of the equipment.
EXCEPT FOR THE WARRANTIES EXPRESSLY SET FORTH
HEREIN, SENSIRION MAKES NO WARRANTIES, EITHER
EXPRESS OR IMPLIED, WITH RESPECT TO THE PRODUCT.
ANY AND ALL WARRANTIES, INCLUDING WITHOUT
LIMITATION, WARRANTIES OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE, ARE EXPRESSLY
EXCLUDED AND DECLINED.
SENSIRION is only liable for defects of this product arising under
the conditions of operation provided for in the datasheet and proper
use of the goods. SENSIRION explicitly disclaims all warranties,
express or implied, for any period during which the goods are
operated or stored not in accordance with the technical
specifications.
SENSIRION does not assume any liability arising out of any
application or use of any product or circuit and specifically
disclaims any and all liability, including without limitation
consequential or incidental damages. All operating parameters,
including without limitation recommended parameters, must be
validated for each customer’s applications by customer’s technical
experts. Recommended parameters can and do vary in different
applications.
SENSIRION reserves the right, without further notice, (i) to change
the product specifications and/or the information in this document
and (ii) to improve reliability, functions and design of this product.
Copyright © 2001 - 2016, SENSIRION.
CMOSens® is a trademark of Sensirion
All rights reserved
Headquarters and Subsidiaries
SENSIRION AG
Laubisruetistr. 50
CH-8712 Staefa ZH
Switzerland
Sensirion Inc., USA
phone: +1 805 409 4900
info-us@sensirion.com
www.sensirion.com
Sensirion Korea Co. Ltd.
phone: +82 31 337 7700~3
info-kr@sensirion.com
www.sensirion.co.kr
phone: +41 44 306 40 00
fax:
+41 44 306 40 30
info@sensirion.com
www.sensirion.com
Sensirion Japan Co. Ltd.
phone: +81 3 3444 4940
info-jp@sensirion.com
www.sensirion.co.jp
Sensirion China Co. Ltd.
phone: +86 755 8252 1501
info-cn@sensirion.com
www.sensirion.com.cn
Sensirion Taiwan Co. Ltd.
phone: +41 44 306 40 00
info@sensirion.com
To find your local representative, please visit www.sensirion.com/contact
www.sensirion.com
Version 2.1 – November 2016
7/7
