Packaging/Process What are the advantages of the BiCMOS process? A BiCMOS process offers the IC designer the ability to use bipolar transistors where speed or voltage-noise levels matter while allowing the use of CMOS transistors where high impedance levels or substantial mixed-signal content is necessary. The VIP50 MOS transistors are optimized to offer analog-grade matching and noise performance. What are the advantages of National''s VIP50 process for low power products? The VIP50 process is a silicon-on-insulator based IC process. SOI processes offer oxide insulation between the circuit elements and the wafer substrate. Oxide insulation results in a strong reduction in parasitic capacitances of the circuit elements. Products implemented in the VIP50 process will have greatly improved bandwidth-to-power ratios compared to conventional technologies. For more information on National''s VIP50 process, technology and products, visit : http://www.national.com/appinfo/amps/vip50.html. What is the material content of the aluminum metalization used on the LMD18200-2D/883? Both layers of metal use the same material: This is 1.0% Si, 0.5% Cu, 98.5% Al Relevant Part: LMD18200-2D/883 Does National Semiconductor use Sumitomo-Bakelift/EME-U series resin to attach the mother board of the I.C.? No, we do not use Sumitomo U-series compounds (resins) on any of our products Relevant Part: Packaging What is the maximum torque that can be applied to the TO-220 tab to mount it onto a PCB? The maximum torque for the T0-220 on 3, 5, 7 and 9 leads (with same body size) is 8 Inch-Lbs. Greater torque can cause damage to the package and device Relevant Part: TO-220 Where should the tab of the TO-263 package be connected? The tab of the TO-263 surface-mount power package should be connected to same PCB copper as the middle lead. For many devices, such as the LM258x boost switching regulators, the LM267x buck switching regulators, and LP396x LDO regulators, this is the ground pin. Check the pinout in the datasheet for each specific device in question Relevant Part: TO-263 Where can I find thermal resistance numbers (Theta JA & Theta JC) for National''s packages? Physical and thermal data for National''s plastic and hermetic packages can be found in the online documents for Plastic Packages and Hermetic Packages. For physical data, see Table 1 in each document; for typical thermal resistances (ThetaJA as a function of airflow, plus ThetaJC), see Table 2 in each document. Where I can find information on the chemical content of National Semiconductor products? To obtain the chemical content of any National Semiconductor product, go to the device''s product folder, scroll down to the table of Package Availability, and click on the package type. This will bring you to the package product folder. The package product folder contains dimensional data and chemical composition for the device in standard and lead-free versions (where both exist). If the product folder for the package in question does not have chemical composition data, please send us a Feedback. For best service, enter in the Comment field the information you require, and in the ProductFolder/PartNumber field identify the product(s) in question. Note that we do not have Material Safety Datasheets (MSDS) for these products, as MSDS do not relate to integrated circuits. Also see information on the Green Project (Banned Substances Program). Do any of National''s packages contain lead which is exempt from the RoHS requirement? High temperature solders with >85% lead are exempt from the RoHS lead prohibition requirement. Some of National''s TO packages contain die attach solders which fall within this category. Products using this high lead die attach, but which are otherwise lead-free, are RoHS compliant. Does National participate in any industry consortia related to lead-free transitioning? Yes, see the following link: http://www.national.com/packaging/leadfree/lf_consortia.html How do I determine if a specific device is available as lead-free? Go to National''s Lead-Free web page within National''s packaging web site and perform a search on the device. Then, in the resulting table, you''ll see the spec "NOPB" for lead-free devices. Is there a change in part number for the lead-free components? National''s strategy is to maintain the same base part number and to include "NOPB" in the spec field to identify lead-free devices. For example, the lead-free version of the LM4890MMX would be identified as "LM4890MMX Spec NOPB" or "LM4890MMX NOPB". Is there a price premium for lead-free products? No. What is the lead-free composition and plating thickness? Package Type Standard Composition Lead-free Composition Lead-free Finish Thickness Leaded Packages and LLP 85Sn / 15Pb Matte Sn 8 microns, minimum 12 microns, nominal (plated) TO-92 85Sn / 15Pb 99.3Sn / 0.7Cu 8 microns, minimum 12 microns, nominal (plated) Micro SMD 63Sn / 37Pb 95.5Sn / 4.0Ag / 0.5Cu N/A Ball Grid Array 63Sn / 37Pb 95.5Sn / 4.0Ag / 0.5 Cu N/A Metal Can (TO-3, TO-5, TO-46) 63Sn / 37Pb 96.5Sn / 3.0Ag / 0.5 Cu 8 microns, minimum (solder dipped) Does National have a web site for its lead-free program? Yes, see the following link: http://www.national.com/packaging/leadfree/ Are the lead-free parts backward compatible with SnPb solder process? National''s lead-free leadframe-based packages are backward compatible. This means that leadframe-based components with matte tin finish can be attached to a PCB using tin/lead solder paste with a tin/lead solder profile (typical peak reflow temperatures ranging from 220oC to 235oC). This is not true for lead-free BGA or microSMD components, which are not compatible with the tin/lead solder process. National''s lead-free LLP package has been shown to be backward compatible. It is recommended that the peak reflow temperature using tin/lead solder paste be 235 - 240oC, with time at over 235oC of 10-30 seconds. How do I order lead-free parts? Please contact National Semiconductor''s local franchised distributor or Customer Support Center and specify "lead-free" or "Spec. NoPb" at the time of your order. Additional information can be obtained from your National Semiconductor sales representative. What are the measured values for the grain size and carbon content for the matte tin plating?   Base Metal  Packages  Average Grain Size (microns)  Average Carbon Conc. (%)  C194  SOIC, SSOP, SOT, MDIP 10.0  0.0355   TAMAC2  TO-220, TO-263 9.3  0.0253   C7025 PQFP, LQFP, TQFP, TSSOP   7.5 0.0034  What information is available relating to tin whiskers? For information on tin whiskers please visit the following link: Tin Whisker Information What tests were included in the lead-free package-level qualification? The moisture sensitivity level (MSL) was reclassified at 260oC for all affected packages. Solderability tests were done on steam aged parts using lead-free solder per the requirements of J-STD-002B. The following reliability tests were run: Preconditioning + Autoclave (96 hours) Preconditioning + Temperature Cycle (-65/150oC for 1000 cycles) Preconditioning + Temperature Humidity Bias (85oC/85% RH for 1000 hours) High Temperature Storage Life (150oC for 1000 hours) What is National''s status on providing lead-free (NOPB) products? All standard products are available in lead-free (NOPB) packaging. To specify NOPB packaging when ordering products, add "/NOPB" to the product part number. For example, to order "LM25575MH" in NOPB, the order number will be "LM25575MH/NOPB". If the product is to be delivered in Tape & Reel carriers, the order number will be "LM25575MHX/NOPB". Please consult our Lead Free Status web page to see the current status and strategies National has in place, as part of the consortia to move to lead-free electronics packaging. Also, please check the "Package Availability, Models, Samples & Pricing Table" on the device''s product folder page for the specific part number you are interested in; there is a column in the Packaging information for "Spec", indicating whether the product is available in non-NOPB as well as NOPB packaging. (To find the product folder page, search for the part in question and follow the link to the product''s "Details".) Are the lead-free parts RoHS compliant? Yes, see National''s green compliance site. http://www.national.com/quality/green/ Which lead-free reflow profile was used by National to qualify lead-free packages? For lead-free qualification National follows the IPC/JEDEC lead-free reflow profile as contained in J-STD-020C. Does National comply with the Banned Substances Program? National''s Green Project was initiated in 2002 in response to increasing customer requests for detailed product content information, specifically focused on the absence of banned substances. The Green Team developed a comprehensive set of procedures and processes to secure conformance to customers'' requirements. See the Green Project overview for details. Where can I find an application note formerly referred to as AN-450, "Understanding Integrated Circuit Package Power Capabilities"? The packaging application note "Understanding Integrated Circuit Package Power Capabilities" was published in some 1990''s National databooks under the titles AN-450 and Appendix E. This document is currently available online, and can be accessed from the "Other Packaging Information" section of the General Packaging Information web page. This application note describes the connection between die temperature and failure rates, as well as between package thermal characteristics and die temperature. Where can I find transistor count on National products, so I can do reliability calculations? Reliability metrics for individual products are given in their product folders (search for the device of interest, and you will either be directed to its product folder, or be given a choice of several possible matches). See information about National''s reliability metrics for further details. National does not publish transistor counts for its products. The traditional reliability calculation based on transistor count is quite meaningless with today''s technology. The reliability of an integrated circuit is related to the impurity level in the silicon and passivation. The impurity level is determined by the chip size and contamination level in the wafer fabrication area, not by the number of transistors on the integrated circuit. Where can I get information on LLP packaging? Information relating to LLP packaging can be found on National Semiconductor''s packaging site What is the thermal resistance of the LM2825N? Thermal resistance junction-to-ambient (ThetaJA) depends on the PCB copper area thermally connected to the LM2825, and can be improved by airflow. With no airflow, ThetaJA is 32C/W for 1 square inch of 1-ounce copper, decreasing to 29C/W for 6 square inches of copper. Adding 500lfm of airflow reduces ThetaJA to 24C/W (for 1 square inch of copper) or 22C/W (for 6 square inches of copper) Relevant Part: LM2825 What is the translation between PCB copper thickness in ounces, inches, and mm? National datasheets often describe PCB copper thickness in terms of ounces. This can be translated as follows:    1 ounce copper = 0.0014 inches = 0.0356mm    2 ounce copper = 0.0028 inches = 0.0711mm.