MS7218-A2 PRESSURE SENSOR DIE (0-18 BAR) FOR HARSH ENVIRONMENT • • • • • 0 to 1800 kPa range (18 bar or 261 PSI) Absolute pressure sensors, Hermetic sensor, temperature up to 150°C Pads on one side RoHS-compatible & Pb-free1 DESCRIPTION The MS7218-A2 is an absolute silicon micro-machined pressure sensor for harsh environment, with the pads on one side. A vacuum reference cavity is sealed on top of the sensitive silicon membrane by the anodic bonding of a glass cap. The pressure, applied on the backside, is converted in electrical signal by piezo-resistors implanted in the silicon membrane. To improve the sensor stability, a drilled glass is bonded on the backside. As the pressure port consists of glass and silicon, both stable in most of the chemicals, the MS7218-A2 is suitable for media-resistive applications. FEATURES • • • Media resistive pressure sensor die Output Span 150mV @ 5 V Temperature Range -40°…+150°C • • • Linearity 0.05% (typical) 2 Die Size 1.73 x 1.18 mm Low Cost, High reliability • • • Tire pressure Engine controls Oil pressure APPLICATION • • • Harsh environments Absolute pressure sensor systems Braking systems ELECTRICAL CONNECTIONS Pin Symbol Description 1 EPI / I diode (-) Epi contact / Cathode of diode (n) 2 Vs+ / I diode (+) Supply voltage / Anode of diode (p) 3 Out+ Positive output* 4 GND Ground 5 Out- Negative output* *Positive output for pressure applied backside 1 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). DA7218-A2_001.doc 007218A21088 ECN 971 Feb. 15, 2008 1/4 PAD OUT Important remarks: The epitaxial layer is not connected to the Vs+ pin on the die, this is to allow temperature measurement with the diode. The epi contact and the cathode of the diode have the same electrical potential. To avoid bias effects, diode and bridge cannot be used simultaneously. As the sensing elements are diffused resistances, the voltage applied on the ground pads (GND) and on the supply voltage (Vs+) have to be lower or equal than the voltage applied on the epi contact (EPI). For better stability it is good to define the potential of the EPI. LAYOUT DA7218-A2_001.doc 007218A21088 ECN 971 Feb. 15, 2008 2/4 FULL SCALE PRESSURE kPa bar mbar PSI atm mm Hg m H2O Inches H2O 1800 18 18000 261 17.8 13501 184 7226 ABSOLUTE MAXIMUM RATINGS Parameter Supply voltage, bridge Supply current diode Storage temperature Pressure overload Symbol Vs+ I diode (+) TS Conditions Min o Ta = 25 C -40 Max Unit 20 100 +150 60 V µA o C Bar ELECTRICAL CHARACTERISTICS (Reference conditions: Supply Voltage VS+ = 5 Vdc; Ambient Temperature Ta = 25°C ) Parameter Operating Pressure Range Min Typ Max Unit 0 18 Bar Operating Temperature Range -40 150 °C Bridge Resistance 3.0 3.4 3.8 kΩ Full-scale span (FS) 120 150 180 mV Zero Pressure Offset -40 0 40 mV Linearity ± 0.05 ± 0.15 Diode forward voltage (VF) 0.550 Temperature Coefficient of Resistance Span Offset Diode + 2400 - 1500 - 80 + 2800 - 1900 + 3300 - 2300 + 80 -2.2 Notes % FS 1 V 2 ppm/°C ppm/°C µV/°C mV/°C 3 2 Pressure Hysteresis ± 0.05 ± 0.15 % FS 4 Repeatability ± 0.05 ± 0.15 % FS 5 0.3 % FS 6 Temperature Hysteresis NOTES 1) Deviation at one half full-scale pressure from the least squares best line fit over pressure range (0 to 18 bar). 2) The forward voltage of the diode is measured when driving it with a typical value of 40 µA. 3) Slope of the endpoint straight line from 25°C to 60°C. 4) 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. 5) Same as 3) after 10 pressure cycles. 6) Maximum difference in offset after one thermal cycle from -40°C to +150°C. TEMPERATURE COMPENSATION The diode between the piezo diffusion and the epi contact can be used for temperature measurement. The forward voltage of the diode is measured on I diode (-) when a typical current of 40 µA fed in I diode (+). Temperature measurement cannot be done at the same time as pressure sensing due to bias effects. DA7218-A2_001.doc 007218A21088 ECN 971 Feb. 15, 2008 3/4 PICKING TOOLS 2 2 The MS7218-A2 sensors have a topside glass cap (1.05 x 1.18 mm ) and a backside glass (1.73 x 1.18 mm ). The pick and place tool has to be of a soft material as rubber (Hardness 78-97 Shore A). Its external size must fit the glass cap. Successful tests were done with some tools of SPT (see SPT drawing and references bellow). SPT references External dimension Internal dimensions RTR-A2-045x045 TL & TW: 0.045 inch /1.14 mm ∅H: 0.025 inch / 0.63 mm WIRE BONDING 2 2 The bondable area is 100 x 100 µm for the EPI pad and 100 x 285 µm for the other pads. The location of the bonding pads is close to the top Pyrex glass edge reducing the possible size and angle of the bonding capillary. Refer to the detail view D on the layout for more precision. ORDERING INFORMATION Product Code MS7218-A2 type Absolute Product 18 bar pressure sensor sawn on b/f Art.-Nr. 721825023 The MS7218-A2 dice are supplied sawn on blue foil, mounted on plastic rings. FACTORY CONTACTS Intersema Sensoric SA Ch. Chapons-des-Prés 11 CH-2022 BEVAIX SWITZERLAND Tel. 032 847 9550 Tel. Int. +41 32 847 9550 Telefax +41 32 847 9569 e-mail: http://www.intersema.ch 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. DA7218-A2_001.doc 007218A21088 ECN 971 Feb. 15, 2008 4/4