Automotive Electronics
Pressure sensor
for passive safety applications
SMD187
Overview
The SMD187 is a pressure sensor component designed for
peripheral pressure sensors used in many airbag systems,
whereas the sensor component shall be implemented in
satellite housing. Main purpose of the SMD187 is to sense
the pressure change in peripheral cavities like the sidedoors due to deformations and to provide high speed crash
information for the firing algorithm of the central electronic
control unit (ECU).
Product description
The SMD187 pressure sensor component can measure the
Pressure sensor SMD187 for airbag systems
Customer benefit / features:
absolute atmospheric pressure in the range of 50 kPa up to
126.5 kPa and is capable to sense pressure changes of 5 %/+15 % relative to the absolute pressure. If no pressure
change occurs the relative pressure signal equals to zero.
 Highly reliable two-wire current interface for digital
transmission of pressure data (PSI5 interface)
 Transmission of pressure change and absolute pressure
 Transmission of a unique serial part number and
status data during start-up
The pressure signal of the sensor element is digitized, temperature compensated, filtered and subsequently processed by the integrated interface ASIC to generate a relative pressure change signal independent from the ambient
pressure. The ASIC also controls the overall system timing,
 Power-on sensor self-test
the initialization, the self-test, the p0-adjustment and the
 Surface-micro machined sensor element
data communication. Hence, the implemented self-test and
 Absolute pressure range: 0.500 to 1.265 bar (12 bit)
the signal conditioning provide accurate, reliable and fast
 Relative pressure range: -5 to +15 % (10 bit)
pressure information needed for passive safety systems.
The SMD187 sensor is applicable in the temperature range
from -40 °C...+125 °C and operates with a supply voltage of
typical 6.9 V.
Automotive Electronics | SMD187
Working principle
Parameters SMD187
Measurement and functional characteristics
The pressure sensor converts the deflection of a micromechanical (MEMS) diaphragm into an analog signal repre-
Absolute pressure range
0.5…1.265 bar
Resolution abs. pressure
12 bit
Range of pressure change
Resolution of pressure
-5…+15 %
Sensitive Δp/p
P0 adjustment rate
20.48 LSB/%
3dB corner frequency
426 Hz
Transmission bit rate
125 kBit/s
Period of data transmission
227.5 µs
face PSI5 with a resolution of 10 bit for relative pressure
Operating temperature
-40 °C…+125 °C
sensor output is mapped into 10 bit words.
Supply voltage
5...11 V; typical 6.9 V
Sweep current (20 mA)
17...23 mA
Sweep current (35 mA)
30...40 mA
10 bit
< 0.5 kPa/s
of the diaphragm is measured by means of piezo-resistive
elements where the T-diode provides temperature data for
trimming purposes.
Interface
The SMD187 transmit all data via a peripheral sensor intersignals. Absolute pressure resolution is 12 bit, where as the
Operating conditions
1)
senting the absolute atmospheric pressure. The deflection
Over lifetime and temperature
Package
The SMD187 pressure sensor component is shipped in a
Mold-Premold MPM package with 16 pins. Peripheral pressure sensors with built-in SMD187 and digital 2-wire PSI5
interface are also available.
Outline Mold-Premold (MPM) SOIC16 package
Portfolio
The SMD187 sensor is part of a larger sensor portfolio. The
portfolio consists of acceleration sensors, angular rate sensors, pressure sensors, and combined inertial sensors for
occupant safety systems, vehicle dynamics control VDC, active suspension systems, motor management, transmission
control systems, and navigation.
Bosch has been active in the field of micro-electromechanical systems (MEMS) for more than 20 years, and is
established as one of the pioneers of this technology. With
more than 1000 MEMS patents, hundreds of engineers in
this field, and more than 3 billion MEMS sensors shipped
to date, Bosch is the global market leader for MEMS sensors.
Dimensions in millimeters
For more information about automotive MEMS sensors,
visit www.bosch-sensors.com.
Regional sales contacts
Europe/Japan bosch.semiconductors@de.bosch.com
USA/Canada bosch.semiconductors@us.bosch.com
China
bosch.semiconductors@cn.bosch.com
Korea
bosch.semiconductors@kr.bosch.com
www.bosch-semiconductors.com
www.bosch-sensors.com
Robert Bosch GmbH
Automotive Electronics
AE/SCS
Postfach 13 42
72703 Reutlingen
Germany
www.bosch.de
© Robert Bosch GmbH 07/2013. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications
for industrial property rights. The information provided is for information purposes only and does not constitute a legal obligation or a warranty, express or implied,
concerning quality, marketability or suitability for a specific purpose. The designs incorporated in vehicles and the performance of the designs may vary depending on
the vehicle manufacturer's specifications and requirements for the product. We reserve the right to make product changes, adaptations and modifications without prior
notice.