MS7901 PRESSURE SENSOR DIE (0-1 BAR) • 0 to 100 kPa range (1 bar or 14.5 PSI) • Absolute/differential pressure sensors • RoHS-compatible & Pb-free1 DESCRIPTION The sensor element of the MS7901 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 (MS7901-A_0.2) or 0.5 mm (MS7901-A_0.5). There are two gauge versions available: one with a drilled Pyrex glass (MS7901-D) and the other without Pyrex glass (MS7901-S). FEATURES • • • Uncompensated pressure sensor die Output span 150mV @ 5V Temperature range -40°…+125°C • • • Linearity 0.05% (typical) Very small die size 1.78 x 1.78 mm (MS7901-A) Low cost, high reliability • • Barometers, altimeters Variometers APPLICATION • • Absolute pressure sensor systems Differential/gauge pressure sensor systems ELECTRICAL CONNECTIONS Positive output for pressure applied topside Vs+ / EPI Vs+ : Supply voltage of Wheatstone bridge Epi : Connection of epitaxial layer (membrane) Out- : Negative output Out+ : Positive output Out- Out+ GND1 : Ground GND2 : Ground R5+ R6+ R5- R5+ : Reference Resistor 5: positive access R5 and R6 are placed on bulk GND1 GND2 R6- R5- : Reference Resistor 5: negative access R6+ : Reference Resistor 6: positive access R6- : Reference Resistor 6: negative access 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). DA7901_005.doc 00007901872 ECN 1178 January 23rd, 2009 1/5 BOND PAD CONFIGURATION Vs+/Epi OutMS7901 Important remarks: R5+ R6+ R5- R6- 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+). The epitaxial layer is connected to the Vs+ pin under the pad. Out+ GND1 GND2 LAYOUT (Absolute sensors) MS7901-A_0.2 MS7901-A_0.5 Pad opening in passivation is 100 µm DA7901_005.doc 00007901872 ECN 1178 January 23rd, 2009 2/5 LAYOUT (Gauge sensors) MS7901-D MS7901-S Pad opening in passivation is 100 µm FULL SCALE PRESSURE kPa bar mbar PSI atm mm Hg m H2O Inches H2O 100 1 1000 14.5 0.987 750 10.197 401 ABSOLUTE MAXIMUM RATINGS Parameter Supply voltage Storage temperature Pressure overload DA7901_005.doc 00007901872 ECN 1178 Symbol VS+ TS Conditions Min Max Unit -40 20 +150 5 V C Bar o Ta = 25 C January 23rd, 2009 o 3/5 ELECTRICAL CHARACTERISTICS (Reference conditions: Supply Voltage VS+ = 5 Vdc; Ambient Temperature Ta = 25°C ) Parameter Min Operating Pressure Range Typ Max Unit Notes 0 1 Bar Operating Temperature Range -40 125 °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 ± 0.05 ± 0.2 + 2800 - 1900 + 3300 - 2300 + 80 ppm/°C ppm/°C µV/°C Pressure Hysteresis ± 0.05 ± 0.15 % FS 4 Repeatability ± 0.05 ± 0.15 % FS 5 0.3 % FS 6 Linearity Temperature Coefficient of Resistance Span Offset + 2400 - 1500 - 80 Temperature Hysteresis % FS 1 2 3, 1 NOTES 1) 2) 3) 4) Reference Resistors R5 and R6 have the same specifications as the bridge resistances. Deviation at one half full-scale pressure from the least squares best line fit over pressure range (0 to 1 bar). Slope of the endpoint straight line from 25°C to 60°C. 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 +125°C. PICKING TOOLS The MS7901 sensors have a sensitive membrane size of 0.74 x 0.74 mm and outer dimensions of 1.78 x 1.78 mm (MS7901-A_0.2, MS7901-A_0.5 and MS7901-D) and 1.8 x 1.8 mm (MS7901-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 DA7901_005.doc 00007901872 ECN 1178 RTR-A1-060x060 TL & TW: 0.06 inch /1.52 mm ∅H: 0.035 inch / 0.89 mm January 23rd, 2009 4/5 ORDERING INFORMATION Product Code Type Product Art.-Nr. MS7901-A_0.2 Absolute 1 bar Pressure Sensors 0.2 mm Pyrex sawn on b/f 790125022 MS7901-A_0.5 Absolute 1 bar Pressure Sensors 0.5 mm Pyrex sawn on b/f 790125021 MS7901-D Differential 1 bar Pressure Sensors sawn on b/f 790125121 MS7901-S Differential 1 bar Pressure Sensors no pyrex sawn on b/f 790125221 The MS7901 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. DA7901_005.doc 00007901872 ECN 1178 January 23rd, 2009 5/5