MS7904
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•
•
•
•
DESCRIPTION
PRESSURE SENSOR DIE (0-4 BAR)
0 to 400 kPa range (4 bar or 58 PSI)
Absolute/differential pressure sensors
High linearity, small size
High overpressure capability (15 bar)
RoHS-compatible & Pb-free
1
The sensor element of the MS7904 consists of a silicon micro-machined membrane. Implanted resistors make
use of the piezo-resistive effect to sense the membrane deflection and transform it in an electrical signal. This
sensor, which has outstanding linearity and span values, is available in various configurations. The absolute
pressure sensor employs a sealed vacuum reference cavity underneath the membrane. The Pyrex glass wafer
used for this sealing has a thickness of 0.2 mm (MS7904-A_0.2) or 0.5 mm (MS7904-A_0.5). Two gauge
versions are available: one with a drilled Pyrex glass (MS7904-D) and the other without Pyrex glass (MS7904-S).
FEATURES
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•
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Uncompensated pressure sensor die
Output span 150mV @ 5V
Temperature range -40°
…+125°
C
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Linearity 0.05% (typical)
Very small die size 1.72 x 1.58 mm (MS7904-A)
Low cost, high reliability
APPLICATION
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Absolute pressure sensor systems
Differential/gauge pressure sensor systems
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Engine controls
Dive computers
ELECTRICAL CONNECTIONS
Positive output for pressure applied topside
Vs+
EPI
Vs+ : Supply voltage of Wheatstone bridge
Epi : Connection of epitaxial layer (membrane)
Out+
Out-
Out- : Negative output
Out+ : Positive output
GND1 : Ground
GND2 : Ground
GND1
1
GND2
The European RoHS directive 2002/95/EC (Restriction of the use of certain Hazardous Substances in electrical and electronic equipment)
bans the use of lead, mercury, cadmium, hexavalent chromium and polybrominated biphenyls (PBB) or polybrominated diphenyl ethers
(PBDE).
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BOND PAD CONFIGURATION
Vs+
Epi
Out-
Important remarks:
As the sensing elements are diffused resistances, the voltage
applied on the ground pads (GND1 and GND2) has to be lower
than the voltage applied on supply voltage pad (Vs+).
MS7912
The epitaxial layer is connected to the Vs+ pin under the pad.
Gold ball bonding or aluminium wedge bonding can be used to
wire-bond the sensor. The quality of the wire-bonding is equipment
and process dependant. For this reason, it is strongly
recommended that a thorough wire-bonding qualification is made
by the end user if the sensor is going to be operated over an
extended temperature range.
Out+
GND1
GND2
LAYOUT (Absolute sensors)
MS7904-A_0.2
MS7904-A_0.5
Pad opening in passivation is 100
µ
m
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LAYOUT (Gauge sensors)
MS7904-D
MS7904-S
Pad opening in passivation is 100
µ
m
FULL SCALE PRESSURE
kPa
400
bar
4
mbar
4000
PSI
58
atm
3.948
mm Hg
3000
m H
2
O
40
Inches H
2
O
1607
ABSOLUTE MAXIMUM RATINGS
Parameter
Supply voltage
Storage temperature
Pressure overload
Symbol
VS+
T
S
Ta = 25 C
-40
o
Conditions
Min
Max
20
+150
15
Unit
V
C
Bar
o
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ELECTRICAL CHARACTERISTICS
(Reference conditions: Supply Voltage VS+ = 5 Vdc; Ambient Temperature Ta = 25° )
C
Parameter
Operating Pressure Range
Operating Temperature Range
Bridge Resistance
Full-scale span (FS)
Zero Pressure Offset
Linearity
Temperature Coefficient of Resistance
Span
Offset
Pressure Hysteresis
Repeatability
Temperature Hysteresis
NOTES
Min
0
-40
3.0
120
-40
Typ
Max
4
125
Unit
Bar
°
C
KΩ
mV
mV
% FS
ppm/°
C
ppm/°
C
µV/°
C
% FS
% FS
% FS
Notes
3.4
150
0
± 0.05
3.8
180
40
± 0.15
+ 3300
- 2300
+ 80
± 0.15
± 0.2
0.3
1
2
+ 2400
- 1500
- 80
+ 2800
- 1900
± 0.05
± 0.1
4
5
6
1) Deviation at one half full-scale pressure from the least squares best line fit over pressure range (0 to 12 bar).
2) Slope of the endpoint straight line from 25° to 60°
C
C.
3) Output deviation at any pressure within the specified range, when this pressure is cycled to and from the
minimum or maximum rated pressure, at 25°
C.
4) Same as 3) after 10 pressure cycles.
5) Maximum difference in offset after one thermal cycle from -40° to +125°
C
C.
PICKING TOOLS
The MS7904 sensors have a sensitive membrane size of 0.5 x 0.5 mm and outer dimensions of 1.72 x 1.58 mm
(MS7904-A_0.2, MS7904-A_0.5 and MS7904-D) and 1.75 x 1.61mm (MS7904-S). The pick and place tool has
to be of a soft material such as rubber (Hardness 78-97 Shore A). Its external size must fit the sensor and the
vacuum cavity must be as large as the membrane itself. Successful tests have been made with specific SPT
tools, see SPT drawing and references below.
Ensure that the ejection pins do not touch the membrane for gauge versions.
SPT references
External dimension
Internal dimensions
RTR-A1-060x060
TL & TW: 0.06 inch /1.52 mm
∅H:
0.035 inch / 0.89 mm
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ORDERING INFORMATION
Product Code
MS7904-A_0.2
MS7904-A_0.5
MS7904-D
MS7904-S
Type
Absolute
Absolute
Differential
Differential
Product
4 bar Pressure Sensors 0.2 mm Pyrex sawn on b/f
4 bar Pressure Sensors 0.5 mm Pyrex sawn on b/f
4 bar Pressure Sensors sawn on b/f
4 bar Pressure Sensors no Pyrex sawn on b/f
Art.-Nr.
790425022
790425021
790425121
790425221
The MS7904 dice are supplied sawn on blue foil, mounted on plastic rings.
FACTORY CONTACTS
Factory and European Sales office
Intersema Sensoric SA
Ch. Chapons-des-Prés 11
CH-2022 Bevaix
Switzerland
Phone:
+41 32 847 9550
Fax:
+41 32 847 9569
e-mail:
Website:
www.intersema.ch
USA
Measurement Specialties Inc.
1000 Lucas Way
Hampton, VA 23666
USA
Phone:
Fax:
e-mail:
Website:
+1 800 555 1551
+1 757 766 4297
sales@meas-spec.com
www.meas-spec.com
ASIA
Measurement Specialties (China), Ltd.
F1.6-4D, Tian An Development
Compound
Shenzhen, China 518048
Phone:
Fax:
e-mail:
Website:
+86 755 8330 1004
+86 755 8330 6797
pfc.cs.asia@meas-spec.com
www.meas-spec.com
NOTICE
Intersema reserves the right to make changes to the products contained in this data sheet in order to improve the design or performance
and to supply the best possible products. Intersema assumes no responsibility for the use of any circuits shown in this data sheet, conveys
no license under any patent or other rights unless otherwise specified in this data sheet, and makes no claim that the circuits are free from
patent infringement. Applications for any devices shown in this data sheet are for illustration only and Intersema makes no claim or
warranty that such applications will be suitable for the use specified without further testing or modification.
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