1、 ANSI/VITA 48.5-2010 VITA Copyright VITA 2010. All Rights Reserved. PO Box 19658, Fountain Hills, AZ 85269 480-837-7486 Approved ANSI Standard ANSI/VITA 48.5 Mechanical Standard for Electronic Plug-in units Using Air Flow Through Cooling Abstract This standard establishes the design requirements f
2、or an air-flow-through cooled plug-in unit with a form factor as close to 6U as possible while retaining the VITA 46 connector layout. Unlike ANSI/VITA 48.1, which uses cooling air impinged directly upon the components and circuit boards, this plug-in unit uses a compact core heat exchanger located
3、within the central heat sink of the unit. Approved: September 2010 American National Standards Institute, Inc. Secretariat: VITA ANSI/VITA 48.5-2010 Copyright VITA 2010. All Rights Reserved. Notices American National Standard Approval of an American National Standard requires verification by ANSI th
4、at the requirements for due process, consensus, and other criteria for approval have been met by the standards developer. Consensus is established when, in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substa
5、ntial agreement means much more than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be considered, and that a concerted effort be made toward their resolution. The use of American National Standards is completely voluntary; their existence does not
6、 in any respect preclude anyone, whether he has approved the standards or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standards. The American National Standards Institute does not develop standards and will in no circumstances giv
7、e an interpretation of any American National Standard. Moreover, no person shall have the right or authority to issue an interpretation of an American National Standard in the name of the American National Standard Institute. Requests for interpretations should be addressed to the secretariat or spo
8、nsor whose name appears on the title page of this standard. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this standard. P
9、urchases of American National Standards may receive current information on all standard by calling or writing the American National Standards Institute. NOTE: The users attention is called to the possibility that compliance with this standard may require use of an invention covered by patent rights.
10、 By publication of this standard, no position is taken with respect to the validity of this claim or of any patent rights in connection therewith. The patent holder has, however, filed a statement of willingness to grant a license under these rights on reasonable and nondiscriminatory terms and cond
11、itions to applicants desiring to obtain such a license. Details may be obtained from the standards developer. COPYRIGHT NOTICE Published by: VITA PO Box 19658, Fountain Hills, AZ 85269 Copyright 2010 by VITA All rights reserved. Except for employees of VITA member companies, no part of this publicat
12、ion may be reproduced in any form, in an electronic retrieval system or otherwise, without prior written permission of the publisher. Printed in the United States of America - R1.0, ISBN 1-885731-62-0. ANSI/VITA 48.5-2010 Copyright VITA 2010. All Rights Reserved. Comments, Corrections, and/or Additi
13、ons Anyone wishing to provide comments, corrections and/or additions to this draft specification please direct them to the Technical Director at the VITA office. VSO and Other Standards Should anyone want information on other standards being developed by VSO, VME Product Directories, VME Handbooks,
14、 or general information on the VME market, please contact the VITA office at the address or telephone number given on the front cover. ANSI/VITA 48.5-2010 Copyright VITA 2010. All Rights Reserved. Table of Contents 1! Scope 5! 1.1! Purpose . 5! 1.2! Mechanical Characteristics 5! 1.3! Terminology . 5
15、! 1.3.1! Abbreviations 5! 1.3.2! 2-level Maintenance (2LM). 6! 1.3.3! Special Word Usage. 6! 2! References 8! 2.1! 2.1 General References. 8! 3! Definitions 9! 4! Plug-in unit requirements 10! 4.1! Plug-in unit description 10! 4.2! Plug-in unit construction 13! 4.3! Clearances, Profile, and Pitch .
16、13! 4.4! Plug-in unit identification 13! 4.5! Thermal requirements 14! 4.6! Reliability . 14! 4.7! Plug-in unit warp 14! 4.8! Personnel safety 14! 4.9! Plug-in unit covers . 14! 4.10! EMI and ESD . 14! 4.11! PWB characteristics. 14! 4.12! Materials 14! 4.12.1! Toxic outgassing 15! 4.12.2! Flammable
17、material 15! 4.12.3! Material affected by fungus 15! 4.12.4! Adhesive backed labels . 15! 4.12.5! Hazardous components and materials. 15! 4.13! Finishes and protective treatments 15! 4.13.1! Conformal coating 15! 5! Plug-in unit interface requirements 16! 5.1! Mechanical configuration . 16! 5.2! Plu
18、g-in unit span 16! 5.3! Plug-in unit Pitch 16! 5.4! Heat exchanger (core)/plug-in unit frame 18! 5.5! Plug-in unit guide requirements . 18! 5.5.1! Plug-in unit guide structure. 18! 5.5.2! Plug-in unit guide material 18! 5.5.3! Plug-in unit guide conductive path . 19! 5.6! Plug-in unit header structu
19、re 19! 5.7! Connector 19! 5.8! Plug-in unit keying . 19! 5.9! Durability 19! ANSI/VITA 48.5-2010 Copyright VITA 2010. All Rights Reserved. 5.10! Plug-in unit insertion and extraction. 20! 5.10.1! Plug-in unit insertion lever material 20! 5.11! Plug-in unit retainers 20! 6! Chassis Recommendations fo
20、r VITA48.5 Plug-in Units 21! 6.1! Connectors 21! 6.2! Chassis 21! 6.2.1! Chassis dimensions . 21! 6.2.2! Chassis seal . 28! 6.3! Component Placement 29! 6.4! Weight 29! 6.5! Thermal considerations . 29! 6.5.1! Mass airflow control 30! 6.6! Mechanical bonding. 30! 7! Appendix A: Acknowledgements. 31!
21、 7.1! Working Group Members. 31!List of Tables Table 1-1: Term Definitions 9! Table 3-1: Working Group Members 31!List of Figures Figure 1 - Air-Flow-Through Plug-in Unit . 10! Figure 2 - Air-Flow-Through Plug-in Unit . 11! Figure 3 - Air-Flow-Through Plug-in unit 12! Figure 4 - Air-Flow-Through Plu
22、g-in unit 13! Figure 5 - Dimensional Requirements for Air-Flow-Through Plug-in unit 17! Figure 6 - Dimensional Recommendations for Injector / Extractor 18! Figure 7 Chassis Dimensional Recommendations . 22! Figure 8 Chassis Dimensional Recommendations . 23! Figure 9 Chassis Dimensional Recommendatio
23、ns . 24! Figure 10 Chassis Dimensional Recommendations . 25! Figure 11 Chassis Air Seal Recommendations 26! Figure 12 Chassis Air Seal Recommendations 27! Figure 13 Chassis Air Seal Recommendations 28! ANSI/VITA 48.5-2010 Copyright VITA 2010. All Rights Reserved. Page 5 1 Scope This standard establi
24、shes the design requirements for an air-flow-through cooled plug-in unit with a form factor as close to 6U as possible while retaining the VITA 46 connector layout. Unlike VITA 48.1, which uses cooling air impinged directly upon the components and circuit boards, this plug-in unit uses a compact cor
25、e heat exchanger located within the central heatsink of the unit. Air is directed through this heat exchanger and the cooling air does not directly contact the components or PWB. Electronics are cooled by either attaching the back of the circuit board to the heatsink, or top cooling the components a
26、gainst the heatsink. The dimensions of the plug-in unit in this document were based on the VITA 48.2 module with the pitch increased to allow for the addition of a compact core heat exchanger between the primary and mezzanine circuit boards. The resulting module pitch is different from other VITA 48
27、 standards. The requirements herein serve to specify the interface control and mechanical design of the plug-in unit as well as the associated chassis. In the event of conflict between the text of this standard and the references cited herein, the text of this standard shall take precedence. Nothing
28、 in this standard however supersedes applicable laws and regulations unless a specific exemption has been obtained. 1.1 Purpose The purpose of this standard is the specification of dimensions and tolerances that will ensure the mechanical intermateability of air-flow-through cooled plug-in units wit
29、hin associated subracks. In addition. mechanical characteristics for applications are also included. 1.2 Mechanical Characteristics This standard covers the basic dimensions, heat exchanger, PWB, material, assembly, and chassis interface for air-flow-through cooled plug-in units. 1.3 Terminology 1.3
30、.1 Abbreviations The following abbreviations are used in this specification: 2LM: 2-level Maintenance EMC: Electromagnetic Compatibility CCA: Circuit Card Assembly ESD: Electrostatic Discharge GND: Safety Ground HP: Horizontal Pitch in.: inch ICD: Interface Control Drawing I/O: Input/Output mm: Mill
31、imeter NRE: Non-recurring engineering PCB: Printed Circuit Board PMC: PCI Mezzanine Card ANSI/VITA 48.5-2010 Copyright VITA 2010. All Rights Reserved. Page 6 PWB: Printed Wiring Board REDI: Ruggedized Enhanced Design Implementation U: Units of 44.45 mm (1.75 in) See ANSI/EIA-310D-1992 and IEC 297-1
32、(1986) XMC: An evolution of the PMC mezzanine card that includes a new connector and the electrical signals necessary for switched communications between the mezzanine card and its carrier. 1.3.2 2-level Maintenance (2LM) Given there is no external standard that establishes specific plug-in unit des
33、ign requirements for 2-level Maintenance compatibility, for the purposes of this specification, all plug-in units will be defined as being 2-level Maintenance compatible. Plug-in units will possess the following attributes: Mechanical protection and handling robustness afforded by covers Compliance
34、with the ESD susceptibility requirements of ANSI/VITA 47 and ANSI VITA 48 1.3.3 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.
35、 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: Rule -: Rules
36、form the basic framework of this 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 impo
37、rtance of the rule. The “shall” or “shall not” words are reserved exclusively for stating rules in this standard and are not used for any other purpose. Recommendation -: Wherever a recommendation appears, designers would be wise to take the advice given. Doing otherwise might result in poor perform
38、ance 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
39、 not” words are reserved exclusively for stating recommendations in this standard and are not used for any other purpose. Suggestion -: 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
40、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 -: In some cases a rule does not specifically prohibit a certain design approach, but the reader might be left wondering whether that approach mig
41、ht violate the spirit of the rule or whether it might lead to some ANSI/VITA 48.5-2010 Copyright VITA 2010. All Rights Reserved. Page 7 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 t
42、he importance of the permission. The lower-case “may” words are reserved exclusively for stating permissions in this standard and are not used for any other purpose. Observation -: Observations do not offer any specific advice. They usually follow naturally from what has just been discussed. They sp
43、ell 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. ANSI/VITA 48.5-2010 Copyright VITA 2010. All Rights Reserved. Page 8 2 Reference
44、s The following publications form a part of this standard to the extent referenced herein. In the event of a conflict between the documents referenced herein and the contents of this standard, the contents of this standard will be considered a superseding requirement. Nothing in this document howeve
45、r supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1 2.1 General References ANSI Y14.5M (1994) Dimensioning and Tolerancing IPC-600 Acceptability of Printed Boards IPC-CC-830 Qualification and Performance of Electrical Insulating Compound for Printed Board
46、Assemblies. IPC-6011 Generic Performance Specification for Printed Boards IPC-6012 Qualification and Performance Specification for Rigid Printed Boards IPC-6013 Qualification and Performance Specification for Flexible Printed Boards IPC-2223 Sectional Design Standard for Flexible Printed Boards ASNI
47、 / VITA 51.0-2008 Reliability Prediction of Electronic Equipment MIL-STD-130 Identification Marking of US Military Property MIL-STD-889 Dissimilar Metals SAE AMS 7290E Decalcomanias ZZ-R-765E (December 1991) Rubber, Silicone A-A-59588 (July 2005) Rubber, Silicone ANSI / VITA 46.0-2007 VPX Baseline S
48、tandard ANSI / VITA 47-2005 (R2007) Environments, Design and Construction, Safety, and Quality for Plug- In Units ANSI / VITA 48.0 (Draft) Mechanical Specifications for Microcomputers Using Ruggedized Enhanced Design Implementation (REDI) ANSI / VITA 42.0-2008 XMC Switched Mezzanine Card Auxiliary S
49、tandard ANSI / VITA 20-2001 (R2005) Conduction Cooled PMC ANSI/VITA 48.5-2010 Copyright VITA 2010. All Rights Reserved. Page 9 3 Definitions The following terms are used within the body of the specification. In this context, they have the following meanings. Term Definition alpha end The end of the plug-in unit nearest the lowest numbered contact. backplane interface plane An assigned plane at the top surface of the backplane used as a reference for plug-in unit dimen
