1、o IINCH-POUNDIMIL-A-28870A19 JANUARY 1990SUPERSEDINGMIL-A-28870(NAVY)S MAY 1982(See 6.8)MILITARY SPECIFICATIONASSEMBLIES, ELECTRICAL BACKPLANE,PRINTED-WIRING,GENERAL SPECIFICATION FORThis specification IS approved for use by all Departmentsand Agencies of the Department of Defense.1. SCOPEo1.1 *. Th
2、is specificationcovers the general requirements forprinted-wiring electrical backplane assemblies consisting of rigidprinted-wiring boards on which separately manufactured compliant-componentparts have been added.Beneficial comments (recormnendations,additions, deletions) and anypertinent data which
3、 may be of use in improving this document should beaddressed to: Commander, Naval Sea Systems Command, SEA 5523, Depart-ment of the Navy, Washington, O.C. 20362-5101 by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426)appearing at the end of this document or by le
4、tter.AMSC N/A FSC 5998DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.oProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-?1.2shall be(a)(b)MIL-A-28870AClassification. Prnted-wiringelectrical backplane assembliesof the f
5、ollowing types.Type 2 - Double-sided printed-wiringelectrical backplaneassemblies.Type 3 - Multilayer printed-wiringelectrical backplane assemblies.2. APPLICABLE DOCUMENTS2.1 Government documents.2.1.1 Specificationsand standards.standards form a part of this document toUnless otherwise specified, t
6、he issues ofin the issue of the t)eoartment of DefenseStandards (DODISS)6.2).SPECIFICATIONSMILITARYMIL-P-116andsupplement theretoMlL-C-28754/39-MIL-C-28859 -MIL-C-28859/l -MIL-C-28859/2 -MIL-C-28859/3 -MIL-C-28859/4 -MIL-C-28859/5 -The following specificationsandthe extent specified herein.these doc
7、uments are those 1IstedIndex of Specificationsand, cited In the solicitation (seePreservation,Methods of.Connectors, Electrical,Modular, Connector, Type II1,Keylng Pegs.Connector Component Parts, Electrical Backplane,Printed-Wiring,General Specification for.Connector Component Parts, Electrical Back
8、plane,Printed Wiring ComplIant Pin.Connector, Component Parts, Electrical Backplane,Printed Wiring, Housing.Connector, Component Parts, Electrical Backplane,Printed Wiring, ComplIant Pin, Feed-Through.Connector, Component Parts, Electrical Backplane,Printed Wiring, Compliant Pin, Feed-To.Connector C
9、omponentPrinted Wiring, LowContact.2Parts, Electrical Backplane,InsertionForce (LIF),CompliantProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-oMIL-I-43553MIL-I-46058MIL-P-5511OSTANDARDSMILITARYDOD-STD-1OOMIL-STD-105MIL-STD-129MIL-STO-202MIL-STD-275MI
10、L-STD-1344MIL-STD-2119MIL-A-28870A- Ink, Marking, Epoxy Base.- InsulatingCompound, Electrical (For Coating PrintedCircuit Assemblies).- Printed-WiringBoards, General Specificationfor.- EngineeringOrawing- Sampling ProceduresAttributes.Prattices.and Tables for Inspectionby- Marking for Shipment and S
11、torage.- Test Methods for Electronicand ElectricalComponentParts.- Printed-Wiringfor Electrical Equipment- Test Methods for ElectricalConnectors.- Printed-WiringElectricalBackplaneAssemblies.MIL-STD-45662 - CalibrationSystems Requirements.MIL-STD-55330 - Connectors, Electricaland Fiber Optic, Packag
12、ingof.(Unless otherwise indicated,copies of federal and militaryspecificationsand standards are available from the Naval PublicationsandForms Center, (ATTN: NPOOS), 5801 Tabor Ave., Philadelphia,PA19120-5099.)2.1.2 Other Government drawinqs. The following other Governmentdrawings form a part of this
13、 document to the extent specified herein.Unless otherwise specified, the issues are those cited in the solicitation.ORAWINGSNaval Avionics Center Orawing No. - SKOGH-0001Naval Avionics Center Drawing No. -“SKOGH-0002(Application for copies should be addressed to the Naval AvionicsoCenter, Code 814,
14、6000 East 21st Street, Indianapolis,IN 46219-2189.)3Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-A-28870A2.2 Non-Government publications. The following documents form a partof this document to the extent specifiedherein, Unless otherwisespecif
15、ied, the issues of the documents which are Department of Defense (DoD)adopted are those listed in the issue of the DODISS cited in thesolicitation, Unless otherwise specified,the issues of documentsnotlisted in the DODISS are the issues of the documents cited in thesolicitation (see 6,2).AMERICAN NA
16、TIONAL STANDARDS INSTITUTE (ANSI)Y32.16 - Standard ReferenceDesignations for ElectricalandElectronicsParts and Equipments.(Application for copies should be addressed to the American NationalStandards Institute, 1430 Broadway,New York, NY 10018-3308.)INSTITUTE FOR INTERCONNECTINGANO PACKAGING ELECTRO
17、NICCIRCUITSSM-840 - Qualificationand Performanceof PermanentCoating (SolderMask) for Printed Boards.(IPC)Polymer(APplication for copies should be addressed toInterconnectingand Packaging ElectronicCircuits,Lincolnwood, IL 60646.)the Institutefor7380 North LincolnAve.,(Non-Governmentstandards and oth
18、er publications are normally availablefrom the organizations that prepare or distribute the documents. Thesedocuments also may be available in or through 1ibrariesor other informationservices.)2.3 Order of precedence. In the event.of a conflict between the textof this document and the references cit
19、ed herein (except for relatedspecification sheets), the text of this document takes precedence. Nothingin this document, however, supersedesapplicable laws and regulationsunlessa specific exemption has been obtained.4Provided by IHSNot for ResaleNo reproduction or networking permitted without licens
20、e from IHS-,-,-o MIL-A-28870A3. REQUIREMENTS3.1 General requirements. Printed-wring electrical backplaneassemblies furnished under this specificationshall be productswhich meetthe requirementsof MIL-STD-2119 and the backplane assembly drawing (see6.2). The printed-wiringelectricalbackplane assemblyd
21、rawtng shall be inaccordance with DOD-STD-1OO. In the event of conflict between MIL-STD-2119and the backplane assemblydrawing, the latter shal1 govern.3.2 Qualification. Printed-wiringelectrical backplane assembliesfurnished under this specificationshal1 be from manufacturerswho areauthorized by the
22、 qualifying activity for 1isting on the applicablequalified manufacturers list at the time of award of contract (see 4.5 andI 6.3).3.3 Material. Acceptance or approval of any constituentmaterial shal1not be construed as a guarantee of the acceptanceof the finishedproduct.I o3.3.1 Compliant component
23、s. The compliant components shall be inaccordance with MIL-C-28859.3.3.2 Housinq and keyinq peqs. The housing (insulator)shall be inaccordancewith MIL-C-28859/2specificationsheet, and the keying pegs shal1be in accordance with MIL-C-28754/39.3.3.3 Printed-wirinqbackplane. Type 2 and type 3 printed-w
24、iringelectrical backplane assemblies shall use rigid printed-wiringboards inaccordance with MIL-P-55110 and the backplane assemblydrawing.3.3.4 Conformal coating and solder mask. Conformal coating or soldermask shall be in accordancewith MIL-I-46058 or IPC-SM-840,Class 3,respectively.3.3.5 Markinq i
25、nk. Marking ink shal1 be an epoxy base ink conformingto MIL-I-43553.o 5Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-A-28870APrinted-wiringelectrical backDlane3.4 Desiqn and construction,assemblIes are composed of housings, compliant components
26、,a rigidprinted-wiring board, and, if specified, keying pegs. The prned-wiringbackplane assemblies shall meet the requirementsof the assembly drawing andthe following requirementsof 3.4.1 through 3.4,4.3.4.1 Housing. The assembled housing dimensions shall be in accordancewith figure 1.3.4.2 Complian
27、t components. The compltant component height above theprinted-wiring board shall be in accordancewith figure 1.3.4.3 Compliant contact component and housing assembly. The compliantcontact component and housing assembly shall be in accordancewith thestandards established on figure 2 when visually ins
28、pectedat a magnificationof 5-10 power. Figure 2A is the preferred condition. Figures 2B through 20are unacceptablee conditions. If more than 5 percent of the receptaclecontacts display any conditionsdepicted on figures 2E through 2H, thebackplane assembly is unacceptable.3.4.4 Wrappost tail tip posi
29、tion. All wrappost tail tip positionsshall be within a positional tolerance of O.O2O inch (0.508mm) diameter tospecified datums on the backplane assembly drawing.3.5 Mechanical requirements.3.5.1 Compliant component retention. The compliantcomponentsinstalled in the rigid printed-wiringboard shall m
30、eet the followingrequirements. There shal1 be no conductive debris anywhere on the assembly.3.5,1.1 Initial After initial insertionof the compliant componentinto the rigified-wiring board, the pushout force shall be a minimum of7.5 pounds (33.4 newton) and a maximum of 45 pounds (200 newton), whente
31、sted in accordancewith 4.7.3.1.3.5.1.2 Conditioned.the pushout force shal1 beAfter conditioning in accordancewith 4.7.3.1.1,a minimum of 7.5 pounds (33.4 newton).6Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-o MIL-A-28870A3.5.1.3 Complant componen
32、t torque. When tested as specified in4.7.3.2, the compliant component shall withstand a minimum torque of 3ounce-inches (0.02 newton-meter). Following removal of the appliedtorque, no displacement or deformation of the compliant component shall beo0visible.3.5.2 Plated-throughhole inteqrity. When mi
33、crosectioned fn accordancewith 4.7,3.5, plated-throughholes containingcompliant components shallmeet the following requirements.3.5.2.1 Hole deformation. The average plated-throughhole deformationshall be no greater than 0.0015 inch (0.0038cm), when measured from thedrilled hole. The absolute maximu
34、m deformation shall be 0.002 inch (0.005cm) (see figure 3).3.5.2.2 Hole wall damaqe. The minimum average copper thicknessremaining between the compliant components and the printed-wiringlaminateshall not be less than 0.0003 inch (0.0008 cm). ln addition, there shall beno copper cracks or other inter
35、plane separationsfrom the hole wal1 barrelor separationsbetween the printed-wiringboard 1aminate and the platedcopper barrel. The sample shall be viewed in the vertical plane to ensurethat no copper cracks, separationsbetween conductor interfaces,orlaminate-to-copperseparations have occurred.3.5.3 H
36、ousinq retention. The housing retention shall be as specifiedin MIL-C-28859/2 (see 4.7.3.3), When housings are removed, they shall bereplaced with an unused housing and the removed housing discarded.3.5.4 Keying peq retention.the keying pegs installed in the5 pounds (22 newtons) minimum.When tested
37、in accordancewith 4.7.3.4,housing shall withstand a removal force of3.5.5 Bow and twist. The maximum allowablebow and twist shall be 1.5percent when tested in accordancewith 4.7.3.6.3.5.6 Engaqinq and seDaratlng forces. The mechanical requirementsforstandard insertion force and Low InsertionForce (L
38、IF) contacts are inaccordancewith 3.5.6.1 and 3.5.6.2.7Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-A-28870A3.5.6.1 Standard insertionengaging and separating force. When testedas specified in 4.7.3.7, the force to engage the tuning fork shall
39、be 6ounces (1.7 newtons) maximum, and the force to separate shal1 be 2 ounces(0.6 newtons) minimum.3.5.6.2 LIF engaging and separating force. When tested as specified in4.7.3.7, the average force to engage shal1 be 2,25 ounces (0.63 newtons)maximum per contact for complete insertion. Separation forc
40、e shall be 4.00ounces (1.12 newtons) maximum per contact.3.5.7 LIF normal force. The average normal force shal1 be greater than3.5 ounces (0.98 newtons)with random reading of not less than 3.00 ounces(0.84 newtons) allowed when tested as specified in 4,7.3.8.3.6 Electrical requirements.3.6.1 Printed
41、-wiringbackplaneto compliant component resistance. Whenthe printed-wiring electrical backplane assemblies are tested as specifiedin 4.7.2.1 and the applIcable figure, the voltage drop shall not exceed 6millivolts (mV) for type 2 assemblies (see figure 4), and 20 mV for type 3assemblies (see figure 5
42、).3.6.2 Insulationresistance. When printed-wiringelectricalbackplaneassemblies are tested as specified in 4.7.2.2, the insulationresistanceshall be as specified In table II.TABLE II. Insulationresistance.Resistance (megohms)Component to componentBefore I Within 1 hour After 2 hourshumidity after rem
43、oval dryingI 10,000 I 10 I 500 I8Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-o00MIL-A-2887GA3.6.3 Dielectric withstanding voltaqe. There shall be no evfdenceofarcing, breakdown or damagewhen tested as spectfied in 4.7.2.3.3.6.4 Circuitry.3.6.4.1
44、Circuit continuity. There shall be no open circuits n thespecimen when tested as specified in 4.7.2.4.1.3.6.4.2 Circuit shorts. There shall be no short circuits In thespecimen when tested as specified in 4.7.2.4.2.3.7 Environmentalrequirements.3.7.1 Temperature CYC1inq. The prfnted-wiringelectricalb
45、ackplaneassembly shal1 show no evtdence of cracking, fracturing,delaminationorother damage detrimental to the operationof the assembly when tested asspecified in 4.7.4.1.3.7.2 Life. The printed-wiringelectrical backplane assembly shallexhibit no =ence of cracks, burns, delaminationor other visual or
46、mechanical damage when tested as specified in 4.7.4.5.3.7.3 Temperature-altitude. There shal1 be no evidence of cracks,burns, or other visible or dimensionaldamage which could cause electricalor mechanical breakdown of the prfnted-wiring electrical backplane assemblywhen tested as specifed in 4.7,4.
47、2. In addition, at the completionof thetemperature-altitudetest, the assembly shall meet the requirementsof 3.6.2(before humidity) and 3.6.3.3.7.4 Vibraton. There shall be no cracking or breaking,nor shallthere be any loosening of parts, or other visible damage when printed-wirtngelectrical backplan
48、e assembliesare tested as specified in 4.7.4.3. Thereshall be no loss of electricalcontinuityof any of the contact circuits ofmore than O.1 microsecond during test. Connectors shall meet therequirementsof 3.5.1 and 3.6.1.9Provided by IHSNot for ResaleNo reproduction or networking permitted without l
49、icense from IHS-,-,-MIL-A-28870A3.7.5 Shock (specifiedpulse. There shal1 be no breakage or looseningof contacts, cracking of inserts,nor other visible or dimensionaldamagewhich could cause electrtcal or mechanical breakdownwhen printed-wiringelectrical backplane assemblies are tested as specified in 4.7,4.4. Thereshall be no loss of electrical continuity of any of the contact circuits ofmore than
