VITA 48.2 Revision D0.06

【实例简介】
VITA 48.2 defines a detailed mechanical implementation for conduction cooling applications applied to PCBs/plug-in units defined in VITA 46. This standard gives the dimensions of associated plug-in units together with applicable detail dimensions of key sub-rack interfaces.
Comments Corrections, and/or Additions Anyone wishing to provide comments, corrections and/or additions to this draft standard please direct them to the draft editor: Mike gust, draft edite Mercury Computer Systems Inc 199 Riverneck road Chelmsford. MA 01824 Ph:978-967-1332 FaX:978-256-4778 Email:mgust@mc.com The best way to provide corrections and additions is via e-mail VSo and other Standards Should anyone want information on other standards being developed by vso, VME Product Directories, VME Handbooks, or general information on the VME market, please contact the ViTA office at the address or telephone number given on the front cover Change Bars All paragraphs changed in this draft are marked with a change bar on the lett side of the paragraph Any table entry that was changed will have a bar on the left side of the table Do not specify or claim conformance to this document Mechanical Specifications for Microcomputers Using REDI, VITA 48.2(Rev. D0. 06 Table of contents 1 Scope 2 Purpose 3 Intellectual Property 4 References ;面,国面 4.1 Terminology 4.1.1 Abbreviations 4.1.2 2 Level Maintenance(2LM) 77778888 41.3 Frame vs Cover 4.1.4 Special word usage…… 5 Circuit board 9 5.1 Circuit board sizes 9 5.2 Conductive elements and guide rails 5.3 Circuit board commonality 10 6 Plug-in unit description 12 7 Plug-in unit si 17 7.1 Plug-in unit height 18 7.2Plug- n unit depth… 18 7.3 Plug-in unit thickness and plug- in unit frame, cover and PCb relationship 7.4 Wedge clamp location 30 7.5 Additional wedge clamp considerations 76 Keying and guide pin/ socket……… 32 7.7 Primary side cover 7.8 Secondary side cover 33 7.9 Plug-in unit insertion/extraction features 33 8 Guidance on cooling 33 9 Position of plug-in unit mounted connectors and backplane mounted connectors 36 9.1 Position of connectors on the plug-in units 36 9.2 Position of backplane mounted connectors 36 9.3 Backplane Rigidity 9.4 Dimensions 37 10Sub-rack∴ 48 11 Filler panels/slot blockers ..8..8... 55 Conduction cooled systems 55 12 EMC 55 13 TWo Level Maintenance(2LM) considerations 55 Appendix A.…..… 56 Tolerance Analysis for 56 Conduction cooled 56 Plug-in Units 56 A1. Overview 57 A2. Plug-in unit Considerations 57 A3, Connector Considerations 59 A4. Sub-rack considerations 60 A5. Analysis approach 63 A5.1 Worst case tolerance analysis .63 A5. 2. Root Sum-of-Square(RSS)tolerance analysis 63 A5.3. Monte Carlo analysis 64 A6. Analysis Results- Secondary Side Wedge Clamp 64 A6. 1. Worst case tolerance analysis 64 A6. 2. Rss tolerance analysis 64 A6.3. Monte Carlo analysis 64 A7. Analysis Results- Primary Side Wedge Clamp……… 66 A7. 1. Worst case tolerance analysis 66 A7.2. Rss tolerance analysis ..67 A7.3. Monte Carlo analysis…….…,,… 67 Do not specify or claim conformance to this document Mechanical Specifications for Microcomputers Using REDI, VITA 48.2(Rev. D0. 06 A8. Wedge clamp side gap considerations 68 A8. 1. Wedge clamp on the secondary side of the plug-in unit 68 A8. 1.1. Worst case tolerance analysis 69 A8.1.2. Rss tolerance analysis ..:::: 69 A8. 2. Wedge clamp on the primary side of the plug-in unit 69 A8.2.1. Worst case tolerance analysis 70 A8.2.2. RSs tolerance analysis 70 A9. Thermal expansion/contraction considerations 70 A10. Summary/conclusion 71 Table of Figures Figure 1. 3U board size Figure 2. 6U board size, component side 1(primary side)view Figure 3. General configuration of 3U conduction cooled plug-in units on 0.80 and 0.85 in centers. 13 Figure 4. General configuration of 30 conduction cooled plug- in units on 1.00 in centers, primary side Wedge clamps. 量国面 13 Figure 5. General configuration of 3U conduction cooled plug-in units on 1.00 in centers, secondary side wedge clamps 14 Figure 6. General configuration of 6U conduction cooled plug-in units on 0.80 and 0.85 in centers.15 Figure 7. General configuration of a 1.00 in. pitch 6U conduction cooled plug- in unit, primary side wedge clamps 16 Figure 8. General configuration of a 1.00 in pitch 6U conduction cooled plug-in unit, secondary side wedge clamps 17 Figure 9. Envelope dimensions for a type 1, 30, 0.80 in pitch conduction cooled plug-in unit assembly .20 Figure 10. Envelope dimensions for a Type 1, 3U,0.85 in. pitch conduction cooled plug-in unit assembly Figure 11. Envelope dimensions for a Type 1, 3U, 1.00 in pitch conduction cooled plug-in unit assembly 22 Figure 12. Envelope dimensions for a Type 1, 3U, 1.00 in. pitch conduction cooled plug-in unit assembly 23 Figure 13 Envelope dimensions for a Type 1, 6U,0.80 in pitch conduction cooled plug-in unit assembly 24 Figure 14. Envelope dimensions for a Type 1, 6U, 0.85 in. pitch conduction cooled plug-in unit Figure 15. Envelope dimensions for a Type 1, 6U, 1.00 in pitch conduction cooled plug-in un s...25 assembly assembly Figure 16 Envelope dimensions for a Type 1, 6U,1.00 in. pitch conduction cooled plug-in unit assembly 27 Figure 17 Envelope dimensions for 3U and 6U conduction cooled plug-in unit assemblies showing the relationship of plug-in unit cover size as a function of plug-in unit pitch 28 Figure 18. Plug-in unit frame-to-PCB relationship. Dimensions shown are applicable to both 3U and 6U form factor plug-in units 29 Figure 19. Location of wedge clamp on 0.80 in pitch plug-in units(3U and 6U)that is compliant with an IEEE 1101.2 compliant sub-rack interface 31 Figure 20. Location of wedge clamp on 0.85 in pitch plug-in units(3U and 6U)that is compliant with an eee 1101.2 compliant sub-rack interface Figure 21. Location of wedge clamp on 1.00 in pitch plug-in units (3 and 6U)that is compliant with an IEEE 1101.2 compliant sub-rack interface 1·面 Figure 22. Location of wedge clamp on 1.00 in pitch plug-in units ( 3U and 6u) that is compliant with an IEEE 1101.2 compliant sub-rack interface Figure 23. Plug-in unit insertion process and required features in the extraction/insertion lever and sub-rack 34 Figure 24. Plug-in unit extraction process and required features in the extraction/insertion lever and sub-rack 35 Figure 25. View of sub-rack showing features required for insertion and extraction 36 Do not specify or claim conformance to this document Mechanical Specifications for Microcomputers Using REDI, VITA 48.2(Rev. D0. 06 5 Figure 26. 3U backplane with plug-in units on 0.80 in centers Figure 27. 3U backplane with plug-in units on 0.85 in centers 39 Figure 28. 3U backplane with plug-in units on 1.00 in centers 40 Figure 29. 6U backplane with plug-in units on 0.80 in centers 丰面国面面 41 Figure 30. 6U backplane with plug-in units on 0.85 in centers 42 Figure 31. 6U backplane with plug-in units on 1.00 in centers 43 Figure 32. 0.80 in plug-in unit pitch backplane populated with 0. 80 in pitch plug-in units 44 Figure 33. 0.85 in. plug- in unit pitch backplane populated with 0.80 and 0.85 in pitch plug-in units.. 45 Figure 34. 1.00 in plug-in unit pitch backplane populated with 0.80, 0.85 and 1.00 in. pitch plug-in units 46 Figure 35. Board, connector, and backplane relationship .47 Figure 36. Compatibility of plug-in units to sub-racks as function of pitch 48 Figure 37. Sub-rack side wall requirements, including provisions for insertion feature 49 Figure 38. 6U plug-in unit, end view defining card guide opening 1国 49 Figure 39. Critical sub-rack dimensions for 3U conduction cooled plug-in units on 0. 80 in. centers.. 50 Figure 40. Critical sub-rack dimensions for 3U conduction cooled plug-in units on 0.85 in. centers.. 50 Figure 41. Critical sub-rack dimensions for 3U conduction cooled plug-in units on 1.00 in centers.51 Figure 42. Critical sub-rack dimensions for 6 conduction cooled plug - in units on 0. 80 in. centers.. 52 Figure 43. Critical sub-rack dimensions for 6U conduction cooled plug-in units on 0.85 in centers.53 Figure 44. Critical sub-rack dimensions for 6U conduction cooled plug-in units on 1.00 in. centers.. 54 Figure A1. Plug-in unit with wedge clamp on secondary side 58 Figure A2. Plug-in unit with wedge clamp on primary side 58 Figure A3. Relationship between the plug-in unit and backplane halves of the connector. 59 Figure A4. Seating of connector on the plug-in unit PCB 60 Figure A5. Positional tolerances for the backplane connectors and guide pins 60 Figure A6. Components of the sub-rack assumed in this tolerance analysis 61 Figure A7. Representative tolerances in an assemble sub-rack 62 Figure A8. Result of Monte Carlo analysis of implementation with wedge clamp on secondary side of the plug-in unit and a nominal0.178mm(0.007in)gap.……………….65 Figure A9. Result of Monte Carlo analysis of implementation with wedge clamp on primary side of the plug-in unit and a nominal 0. 178 mm(0.007 in ) gap 67 Do not specify or claim conformance to this document Mechanical Specifications for Microcomputers Using REDI, VITA 48.2(Rev. D0. 06 1 Scope VITA 48.2 defines a detailed mechanical implementation for conduction cooling applications applied to PCBs/plug-in units defined in VITA 46. This standard gives the dimensions of associated plug-in units together with applicable detail dimensions of key sub-rack interfaces. Two types of plug-in units are defined in this standard. Both Types of plug-in units defined in this standard will take advantage of increased slot pitch and utilization of the secondary side. In addition, both Type 1 and Type 2 plug-in units will also incorporate features to enhance thermal performance and improve structural durability absent and therefore will not be fully compatible with 2 Level Maintenance environmeng 3 The main difference between Type 1 and Type 2 plug-in units is that the type 1 plug- in ur ts will be compatible with 2 Level Maintenance environments. Type 2 plug-in units will have one or more covers The conduction cooled implementations described in this standard are targeted for 3 and 6 form factor plug-in units with PCB and backplane connectors defined in VITA 46. However, in addition to backplane connectors on 0.80 in centers, VitA 48 will also define implementations with backplane connectors on 0.85 and 1.00 in centers 2 Purpose The purpose of this standard is to define the critical dimensions for conduction cooled plug- in units required to ensure the mechanical interchangeability of plug-in units, achieve enhanced packaging density by allowing increased utilization of the secondary side of the PCB and provide sufficient volume for features that can improve both the thermal and structural characteristics of a plug-in unit. The requirements for Type 1 and Type 2 plug-in units will be defined. Also defined are the features/capabilities necessary for type 1 plug-in units to achieve 2 Level maintenance compatibility 3 Intellectual Property The user's attention is called to the possibility that compliance with this standard may require use of one or more inventions covered by patent rights. By publication of this draft standard, no position is taken with respect to the validity of such claims or of any patent rights in connection therewith The patent holder(s)has/have, however, filed a statement of willingness to grant a license under these rights on reasonable and nondiscriminatory terms and conditions to applicants desiring to obtain such a license. Details may be obtained from the standards developer 4 References The following publications shall be used in conjunctions with this standard. When they are superseded by an approved revision, the revision shall apply IEEE Std 1101.1-1998, IEEE Standard for Mechanical Core Specifications for Microcomputers Using IEC603-2 Connectors IEEE Std 1101.2-1992, IEEE Standard for Mechanical Core Specifications for Conduction-Cooled Eurocards VITA46.0(Draft), Advanced Module Format for VMEbuS Systems ANSI/ITA 47-2005, Environments, Design and Construction, Safety, and Quality for Plug-In Units VITA 48.0(Draft)Mechanical Specifications for Microcomputers Using Ruggedized Enhanced Design Implementation(REDI) IEEE Std 1386-2001, IEEE Standard for a Common Mezzanine Card Family: CMC VITA 420(Draft), XMC Switched Mezzanine Card Auxiliary Standard Do not specify or claim conformance to this document Mechanical Specifications for Microcomputers Using REDI, VITA 48.2(Rev. D0. 06 7 4.1 Terminology 4.1.1 Abbreviations The following abbreviations are used in this standard EMC: Electromagnetic Compatibility ESD: Electrostatic Discharge GND: Ground HP: Horizontal Pitch of 5.08 mm(See IEEE Std 1101.1-1991) in. inch ·o: nput/Output mm Millimeter PCB: Printed circuit board PMC: PCI Mezzanine card REDI: Ruggedized Enhanced Design Implementation U: Units of 44 45 mm(1.75 in) [see ANSIEIA-310D-1992 and lEC 297-1 (1986)1 4.1.2 2 Level Maintenance(2LM) Given there is no external standard that establishes specific plug-in unit design requirements for 2 Level Maintenance compatibility for the purposes of this standard, all Type 1 plug-in units will be defined as being 2 Level Maintenance compatible. Type 1 plug-in units will possess the following attributes Mechanical protection and handling robustness afforded by covers Complies with the ESD susceptibility requirements of ANSI/VITA 47 It follows, by definition, that Type 2 plug-in units may not fully posses all of the required design attributes and therefore may not be 2 Level maintenance compatible 4.1.3 Frame vs Cover For conduction cooled applications, plug-in units can use a frame to conduct heat from components to thermal and structural purposes. As a consequence, it may or may not provide adequate eso ily for the edge of the plug-in unit where it is transferred into the sub-rack. The frame is present primarily for protection For VITA 48.2, a cover provides Esd protection by preventing ESD pulses from reaching components a cover can be used in-lieu of a frame or in conjunction with a frame. This can become an important distinction when describing the difference between Type 1 and Type 2 plug-in units 4.1. 4 Special word usage To avoid confusion and to make very clear what the requirements for compliance are, many of the paragraphs in this standard are labeled with keywords that indicate the type of information they contain These keywords are listed below Rule Recommendation Suggestion Permission Observation Any text not labeled with one of these keywords should be interpreted as descriptive in nature. These will be written in either a descriptive or a narrative style The keywords are used as follows Do not specify or claim conformance to this document Mechanical Specifications for Microcomputers Using REDI, VITA 48.2(Rev. D0. 06 Rue≤ chapter>≤ number> Rules form the basic framework of this draft standard they are sometimes expressed in text form and sometimes in the form of figures, tables or drawings. All rules shall be followed to ensure compatibility between board and backplane designs. All rules use the"shall"or shall not"words to emphasize the importance of the rule. Theshall or"shall not"words are reserved exclusively for stating rules in this draft standard and are not used for any other purpose Recommendation <chapter>-<number>: Wherever a recommendation appears, designers would be wise to take the advice given. Doing otherwise might result in poor performance or awkward problems. Recommendations found in this standard are based on experience and are provided to designers to speed their traversal of the learning curve. All recommendations use the"should"or " should not"words to emphasize the importance of the recommendation The"should"or"should not"words are reserved exclusively for stating recommendations in this draft standard and are not used for any other purpose Suggestion <chapter>.<number> A suggestion contains advice, which is helpful but not vital. The reader is encouraged to consider the advice before discarding it. Some design decisions that need to be made are difficult until experience has been gained. Suggestions are included to help a designer who has not yet gained this experience Permission <chapter>.<number> In some cases a rule does not specifically prohibit a certain design approach, but the reader might be left wondering whether that approach might violate the spirit of the rule or whether it might lead to some subtle problem. Permissions reassure the reader that a certain approach is acceptable and will cause no problems. All permissions use the "may" words to emphasize the importance of the permission. The lower-case"may" words are reserved exclusively for stating permissions in this draft standard and are not used for any other purpose Observation <chapter>.<number> Observations do not offer any specific advice. They usually follow naturally from what has just been discussed. They spell out the implications of certain rules and bring attention to things that might otherwise be overlooked. They also give the rationale behind certain rules so that the reader understands why the rule must be followed 5 Circuit board 5.1 Circuit Board sizes Rule 5-1: The PCB sizes targeted by this standard shall be 30 by 160 mm and 6 by 160 mm. See figures 1 and 2 below for the generic baseline 3U and 6U form factor PCBs respectively. Specifics of both the types of connectors and guide sockets used on the PCB can be found in ViTA 46. The PcB outlines are applicable to both Type 1 and Type 2 plug-in units The standalone PCb height in the vicinity of the connectors for a 3U PCB is a maximum of 3. 937 in (100 mm) and for a 6U PCB is a maximum of 9.187 in (233. 35 mm). See figures 1 and 2 for 3U and 6U PCBs respectively Permission 5-1: When incorporated into an actual plug-in unit design, the pcb may be modified appropriately to ensure that the desired level of commonality is obtained such that a common PCB form factor can be used and is compatible with either one or more cover and/or cooling implementations (i.e., air cooling and liquid cooling) Observation 5-1: Specifics for the modifications to the baseline PCB form tactors to make them compatible with multiple cooling implementations are not explicitly defined in this standard Do not specify or claim conformance to this document Mechanical Specifications for Microcomputers Using REDI, VITA 48.2(Rev. D0. 06 9 Observation 5-2: Holes required for attaching covers and/or heat spreaders to the pcb are not defined in this standard; they are left to the implementer to define(size, number, location, etc. 5.2 Conductive elements and guide rails Rule 5-2: For both Types of plug-in units, conductive elements shall not to extend into the interface with the plug-in unit cover (i. e, the plug-in unit cover should not be electrically connected to the board other than to provide a ground ). In addition, printed circuits and components shall be placed on the board in accordance with their electrical requirements/needs 5.3 Circuit Board Commonality Recommendation 5-1: The PCB envelope should be defined such that, at least for a given cooling method, a PCB used in a Type 2 implementation can be used in a Type 1 implementation Recommendation 5-2: In order to minimize the nre associated with going from a Type 2 implementation to a Type 1 implementation, the pcb design should be designed in a manner that minimizes the NrE associated with this transition Factors to consider include: defining appropriate board keep-outs, ensuring maximum component heights are compatible with the use of covers, etc 725] 285 0 21.65 03 852 3937 012 工 50.45 1986 Depth 84.7U 3.335 160 92.35 0.3 3.5636 6.299.000 2 Primary units are in inches and secondary units are in millimeters. Dimensions shown in this figure are for reference only; the actual dimensions are defined in VITA 46 Component side(primary side) view applicable to both Type 1 and Type 2 implementations Figure 1. 3u board size Do not specify or claim conformance to this document Mechanical Specifications for Microcomputers Using REDI, ViTA 48.2(Rev. D0.06) -10- 【实例截图】
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