AN936 Rev 5, 05/2008 Freescale Semiconductor Application Note Mounting Techniques, Lead Forming, and Testing of the MPX Series Pressure Sensors by: Randy Frank INTRODUCTION Freescale’s MPX series pressure sensors are silicon piezoresistive strain-gauges offered in a chip-carrier package (see Figure 1). The exclusive chip-carrier package was developed to realize the advantages of high-speed, automated assembly and testing. In addition to high volume availability and low cost, the chip-carrier package offers users a number of packaging options. This application note describes several mounting techniques, offers lead forming recommendations, and suggests means of testing the MPX series of pressure sensors. Differential Port Option Case 344C-01 Figure 1. MPX Pressure Sensor in Chip-Carrier Package Shown with Port Options Basic Element Case 344-15 Suffix AA Axial Vacuum Port Case 344G-01 Suffix GVSX Dual Port Case 867C-05 Suffix DP Dual Port Case 344C-01 Suffix DP Gauge Port Case 344B-01 Suffix AP/GP Stovepipe Vacuum Port Case 344E-01 Suffix AS/GS Stovepipe Port Case 344A-01 Suffix GVS Axial Port Case 867F-03 Suffix ASX/GSX Axial Port Case 344F-01 Suffix ASX/GSX Basic Element Case 867-08 Suffix A/D Axial Vacuum Port Case 867G-03 Suffix GVSX Figure 2. Chip-Carrier and Available Ported Packages © Freescale Semiconductor, Inc., 2008. All rights reserved. Gauge Port Case 867B-04 Suffix AP/GP Stovepipe Port Case 867E-03 Suffix AS/GS MOUNTING TORQUE .114 .047 0 The sensor package should not be over tightened during mounting to avoid fractures in mounting flanges of port and adhesive bond lines. The recommended torque specification for the sensor packages are as follows: .125 Port Style Torque Limit (max) Single-Sided Port: Port Down Port Up 3 in-lbs 3 in-lbs Dual Port 3 in-lbs Axial Port 3 in-lbs .075 .037R It is recommended that a precision torque wrench be used to ensure these limits are not exceeded. If a torque wrench is not available, theses limits equate to approximately 1/4 to 1/2 turn past finger tight contact. Tightening beyond these limits may result in damage to package, or affect device performance. HARDWARE Screws can be metal or nylon depending on application and customer preference. A #6 button head screw having head diameter of approximately 0.250” is recommended. The larger head diameter will provide force distribution over greater area minimizing potential of damage to part. The screws can be threaded directly into mounting surface or through the board and use a flat washer and nut to secure the device. A locking compound applied to the threads may be desired depending on application. PORT ADAPTERS Available Packages Freescale’s chip-carrier package and available ports for attachment of 1/8” I.D. hose are made from a high temperature thermoplastic that can withstand temperature extremes from -50°C to 150°C (see Figure 2). The port adapters were designed for rivet or 5/32” screw attachment to panels, printed circuit boards, or chassis mounting. 0 Cell .021 Figure 3. Examples of Sensors in Custom Housings The sensor cell may also be glued directly to a custom housing or port using many commercial grade epoxies or RTV adhesives which adhere to grade Valox 420, 30 percent glass reinforced polyester resin plastic or Union Carbide's Udel® polysulfone (MPX2300DT1 only). Freescale recommends using Thermoset EP530 epoxy or an equivalent. The epoxy should be dispensed in a continuous bead around the caseto-port interface shoulder. Refer to Figure 4. Care must be taken to avoid gaps or voids in the adhesive bead to help ensure that a complete seal is made when the cell is joined to the port. The recommended cure conditions for Thermoset EP539 are 15 minutes at 150°C. After cure, a simple test for gross leaks should be performed to ensure the integrity of the cell to port bond. Submerging the device in water for five seconds with full rated pressure applied to the port nozzle and checking for air bubbles will provide a good indication. Adhesive Bead Custom Port Adaptor Installation Techniques The MPX silicon pressure sensor is available in a basic chip-carrier cell which is adaptable for attachment to customer-specific housings/ports (Case 344 for 4-pin devices and Case 867 for 6-pin devices). The basic cell has chamfered shoulders on both sides which will accept an O-ring such as Parker Seal's silicone O-ring (p/n#2-015-S469-40). Refer to Figure 3 for the recommended O-ring to sensor cell interface dimensions. Figure 4. Case to Port Interface AN936 2 Sensors Freescale Semiconductor TESTING MPX SERIES PRESSURE SENSORS must be exercised so that force is not applied to the back metal cap or offset errors can result. Pressure Connection STANDARD PORT ATTACH CONNECTION Testing of pressure sensing elements in the chip-carrier package can be performed easily by using a clamping fixture which has an O-ring seal to attach to the beveled surface. Figure 8 shows a diagram of the fixture that Freescale uses to apply pressure or vacuum to unported elements. When performing tests on packages with ports, a high durometer tubing is necessary to minimize leaks, especially in higher pressure range sensors. Removal of tubing must be parallel to the port since large forces can be generated to the pressure port which can break the nozzle if applied at an angle. Whether sensors are tested with or without ports, care = Diameter Dimensions in 5.72 0.225 MM Inches 3.81 0.150 2.54 0.100 2.39 0.094 φ 0.36 (0.014) M φ 0.36 (0.014) M A B M A B C M M 0.76 0.030 10.16 0.400 3 PL 16.23 0.639 35° ± 2° Section F-F C M 2.03 0.080 14.48 0.570 F 4.55 0.179 3.40 0.134 1.27 0.050 Freescale also offers standard port options designed to accept readily available silicone, vinyl, nylon, or polyethylene tubing for the pressure connection. The inside dimension of the tubing selected should provide a snug fit over the port nozzle. Installation and removal of tubing from the port nozzle must be parallel to the nozzle to avoid undue stress which may break the nozzle from the port base. Whether sensors are used with Freescale’s standard ports or customer specific housings, care must be taken to ensure that force is uniformly distributed to the package or offset errors may be induced. 2.21 2.13 0.087 0.084 3.96 0.156 1.60 0.063 3.96 0.156 6.35 0.250 6.35 0.250 F 13.66 13.51 0.538 0.532 φ 0.36 (0.014) 2 PL M A B M C M 0.36 (0.014) A B C Within Zone -DZone -D- Figure 5. Port Adapter Dimensions AN936 Sensors Freescale Semiconductor 3 C R M B -AN L 1 2 3 4 PIN 1 -T- TOP CLAMP AREA SEATING PLANE J D G F 4 PL 0.136 (0.005) NOTES: DIMENSIONING AND TOLERANCING PER ASME Y14.5M, 1994. CONTROLLING DIMENSION: INCH. DIMENSION -A- IS INCLUSIVE OF THE MOLD STOP RING. MOLD STOP RING NOT TO EXCEED 16.00 (0.630). DIM A B C D F G J L M N R INCHES MIN MAX 0.595 0.630 0.514 0.534 0.200 0.220 0.016 0.020 0.048 0.064 0.100 BSC 0.014 0.016 0.695 0.725 30 NOM 0.475 0.495 0.430 0.450 M T A M STYLE 1: PIN 1.GROUND 2.+ OUTPUT 3.+ SUPPLY 4.- OUTPUT MILLIMETERS MIN MAX 15.11 16.00 13.06 13.56 5.08 5.59 0.41 0.51 1.22 1.63 2.54 BSC 0.36 0.40 17.65 18.42 30 NOM 12.07 12.57 10.92 11.43 Case 344-15 All seals to be made on pressure sealing surface. Figure 6. Chip-Carrier Package Electrical Connection The MPX series pressure sensor is designed to be installed on a printed circuit board (standard 0.100” lead spacing) or to accept an appropriate connector if installed on a base plate. The leads of the sensor may be formed at right angles for assembly to the circuit board, but one must ensure that proper lead form techniques and tools are employed. Hand or “needle nose” pliers should never be used for lead forming unless they are specifically designed for that purpose. Refer to Figure 7 for the recommended lead form technique. It is also important that once the leads are formed, they should not BOTTOM CLAMP AREA Leads should be securely clamped top and bottom in the area between the plastic body and the form being sure that no stress is being put on plastic body. The area between dotted lines represents surfaces to be clamped. Figure 7. Lead Forming be straightened and reformed without expecting reduced durability. The recommended connector for off-circuit board applications may be supplied by JST Corp. (1-800-292-4243) in Mount Prospect, IL. The part numbers for the housing and pins are listed on the following page. CONCLUSION Freescale’s MPX series pressure sensors in the chipcarrier package provide the design engineer several packaging alternatives. They can easily be tested with or without pressure ports using the information provided. AN936 4 Sensors Freescale Semiconductor CONNECTORS FOR CHIP CARRIER PACKAGES MFG/Address/Phone J. S. Terminal Cop. 1200 Business Center Dr. Connector Pin 4 Pin Housing: SMP-04V-BCS SHF-001T-0.8SS 6 Pin Housing: SMP-06V-BC SHF-01T-0.8SS Mount Prospect, IL 60056 (800) 292-4243 Hand Crimper YC-12 Recommended Methode Electronics, Inc. 1300-004 1400-213 Rolling Meadows, IL 60008 (312) 392-3500 1402-213 Requires Hand Crimper 1402-214 Reel TERMINAL BLOCKS Molex 22-18-2043 2222 Wellington Court 22-16-2041 Lisle, IL 60532 (312) 969-4550 Samtec SSW-104-02-G-S-RA P.O. Box 1147 SSW-104-02-G-S New Albany, IN 47150 (812) 944-6733 A 0.002 0.175 ±0.001 0.01 x 45× 4 PL For Vacuum or Pressure Source 0.130 ±0.002 For Retaining Ring (Waldes Kohinoor Inc. Truarc 5100-31) 0.10 0.036 0.038 30° R / A 0.002 TOTAL -A0.125 Dia. 0.311 0.44 Dia. ±0.000 ±0.002 -0.001 0.290 Dia. Dia. 0.648 0.650 Dia. 0.575 Dia. 0.070 Dia. 0.780 Dia. ±0.002 0.670 Dia. 0.015 R 0.02 R 0.04 For O-Ring (Parker Seals 2-015-S469-40) 0.250 0.245 +0.003 0.525- -0.000 0.60 1.00 1.25 Ref A 0.0005 Figure 8. O-Ring Test Fixture AN936 Sensors Freescale Semiconductor 5 How to Reach Us: Home Page: www.freescale.com Web Support: http://www.freescale.com/support USA/Europe or Locations Not Listed: Freescale Semiconductor, Inc. Technical Information Center, EL516 2100 East Elliot Road Tempe, Arizona 85284 +1-800-521-6274 or +1-480-768-2130 www.freescale.com/support Europe, Middle East, and Africa: Freescale Halbleiter Deutschland GmbH Technical Information Center Schatzbogen 7 81829 Muenchen, Germany +44 1296 380 456 (English) +46 8 52200080 (English) +49 89 92103 559 (German) +33 1 69 35 48 48 (French) www.freescale.com/support Japan: Freescale Semiconductor Japan Ltd. Headquarters ARCO Tower 15F 1-8-1, Shimo-Meguro, Meguro-ku, Tokyo 153-0064 Japan 0120 191014 or +81 3 5437 9125 [email protected] Asia/Pacific: Freescale Semiconductor China Ltd. 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