1、Mini-ITX AddendumVersion2.0 Tothe microATX Motherboard Interface SpecificationVersion 1.2 October 2010 1. INTEL CORPORATION(“ INTEL” ) MAKESNOWARRANTIESWITH REGARDTOTHIS SPECIFICATION( “ SPECIFICATION” ), ANDIN PARTICULAR DOESNOTWARRANTOR REPRESENTTHATTHISSPECIFICATIONORANYPRODUCTSMADEIN CONFORMANCE
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6、REPRODUCETHIS SPECIFICATIONFOR ANYPURPOSE PROVIDEDTHIS“ IMPORTANTINFORMATIONANDDISCLAIMERS”SECTION (PARAGRAPHS1-4) IS PROVIDEDIN WHOLEON ANYCOPIES YOURMAKE.NO OTHER LICENSE,EXPRESS OR IMPLIED,BY ESTOPPEL OR OTHERWISE,TO ANY OTHERINTELLECTUALPROPERTY RIGHTSIS GRANTEDHEREIN. Intel is atrademark of Int
7、el Corporationin the U.S.and other countries. *Other names and brands may be claimed as the property ofothers. Copyright ?2010 Intel Corporation 2 Contents Revision History.4 1Executive Summary.5 1.1Terminology.6 1.2ReferenceDocuments.6 1.3Benefits to Users .6 1.4Benefits to Manufacturers . 6 2Layou
8、t .8 2.1Board Dimensions.9 2.2Mounting Hole Placement.9 2.3Connector Placement.11 2.3.1Thin Mini-ITX Back Panel I/O.11 2.4Height Constraints .11 2.4.1Mini-ITX: Primary(Component) Side Height Constraints.11 2.4.2Thin Mini-ITX: Primary (Component) Side Height Constraints.12 2.4.3Secondary (Bottom/Sold
9、er) Side Height Constraints .14 2.4.4Thin Mini-ITX System Considerations .14 3Power Supply Information.16 Figures Figure 1. Example Mini-ITX Layout for SFF Desktop .8 Figure 2. ATX, microATX, and Mini-ITX Mounting Holes.9 Figure 3. Mini-ITX Board Diagram.10 Figure 4. Thin Mini-ITX Back Panel I/O .11
10、 Figure 5. Mini-ITX Maximum Component Height Restrictions.12 Figure 6. Thin Mini-ITX Maximum Component Height Restrictions.14 Tables Table 1. Mini-ITX Addendum Feature Summary.5 Table 2. Compares ATX, microATX, and Mini-ITX Board Dimensions.9 Table 3. Motherboard Mounting Hole Locations.10 3 Revisio
11、n History Revision Number DescriptionRevision Date 2.0Added ThinMini-ITXdefinition.Oct,2010 1.1Minor corrections made. Title changed to:Feb,2009 Min-IiTXAddendum Version 1.1To the microATX MotherboardInterface Specification Version 1.2 to reflect full name ofmATXdocument name. 1.0Initial release.Feb
12、,2009 4 1Executive Summary The Mini-ITX addendum to themicroATX Motherboard Interface Specificationdetails the use the Mini-ITX form factor standard, developed by Via Technologies Inc,for compatibility with Intel based platforms. This document defines onlythe specific features in IntelMini-IsTX base
13、d platforms that differfrom those of microATX and should be used in conjunction with the governing microATX specification. A smaller motherboard layout offers systemdevelopers the ability to create new and innovative systemdesigns. This smaller version of microATX allows and encouragesdevelopers to
14、build within the sub 8 liter chassis volume for a variety of new applications. Described within this document are requirements and characteristics of a Mini-ITX motherboard, so that a motherboard may function and fit appropriately when paired with aMini-ITXchassis. Beyond this, it doesnot detail pro
15、cessor, memory,graphics or other system featuresrequired to meet the Mini-ITX form factor. These items are left to systemdesigners and integrators within the guidelines of the microATX specification. A further refinement of Mini-ITX boards is theThin Mini-ITXboard definition. Its smaller sizeenables
16、 system integrators to integrate sub-4 liter systems,such as Tiny PCs and All-In-One PCs, using a standard building blockapproach. Table 1. Mini-ITX Addendum Feature Summary FeatureBenefit 170mm x 170mm motherboard sizeSmallerboard size enables asmaller system size. Mini-ITX: Standard microATX1.2 or
17、later I/OATXI/Oshielddoes not needto be retooled. panelMotherboardcan be used inan ATX,microATX, or Mini-ITXchassis. Thin Mini-ITX: A Mini-ITXboard targetedforAThin Mini-ITXboard canuse athin back smaller system form factors with a 20mm tallpanel I/O shield whentargetedfor Tiny PCsPCBand component v
18、olumetric, and a1”backand AIOs. The same boardcan be usedin apanel I/Oheight Mini-ITX,microATX, and ATXchassis when usedwith a regular ATX I/Oshield. Same motherboard mounting holes as inCompatible with microATXchassis. Noneedto microATXretool current chassis. Current processor and future processorC
19、hassis will work for multi generation socketed technologiesprocessor technology. This addendum does NOT define: Specificpower supply form factors Thermal design guidance to chassis vendors (covered in TASC guide listed in ReferenceDocuments) 5 The Mini-ITX Addendum To the microATX Motherboard Interf
20、ace Specificationis a public document intended for widespread application in many types of systems. It is available through a public website located at: http:/www.formfactors.org 1.1Terminology TermDescription Small FormFactor (SFF)8-19liter chassis(IDC*definition) UltraSFF (uSFF)4-8 liter chassis (
21、IDC*definition) Tiny PCLessthan 4 literchassis (IDC*definition) All-In-One (AIO) PCAnAll-In-One is adesktop PC with adisplay builtinto the main computing unit (IDC*definition) 1.2Reference Documents The following referencedocuments are posted on the public web siteat: http:/www.formfactors.org Docum
22、ent microATXMotherboard InterfaceSpecification Version1.2 SFX12V PowerSupply DesignGuide TFX12V PowerSupply Design Guide Thermally Advantaged Small Chassis orTASC pronounced task (Thermal Design Guide) 1.3Benefits to Users Trends in the industry indicatethat users require a smaller and lower cost so
23、lution for their PC needs. Mini-ITX smaller board size and lower height keep-out zones enable a reduced sized chassis as it sits on the user s desk,is mounted on a di,soprlay comes in any other innovative form factor. These changesalso enable a PC to be designed into various aesthetic shapes and siz
24、es. The Thin Mini-ITX board variation leverages Mini-ITX s advantages, whileenabling even thinner systems. 1.4Benefits to Manufacturers By manufacturing to the standard or thin variations of the Mini-ITX specification, motherboard manufacturers and chassis manufacturerscan guarantee a better 6 compa
25、tibility between their products. Theycan also capitalize on the benefits of a reduction in total system costs because of a reduced system size. This specification allows chassis vendors to design their product targeting the soldered down, low power processors all the way up to high performance, mult
26、i-core processors. It eliminates the need for them to design targeted chassis for each platform. 7 2Layout This section describes the mechanical specifications of the Mini-ITX and Thin Mini-ITX form-factor motherboards. Size, mounting hole placement, connector placement, and component height constra
27、ints are specified. System components such as hard drives, disk drives, and powersupplies are not specified; however,it is generallyrecommended to consider what would facilitate assembly, as well as not place components such that they block fan inlets. An example layout is depicted in Figure 1. Thin
28、 Mini-ITX is a variant of standard Mini-ITX and shares most of the same requirements. Requirements areonly different where new specifications are specifically defined for Thin Mini-ITX. Figure 1. Example Mini-ITX Layout for SFF Desktop NOTE:Depicted systemis approximately 8L with standard desktop co
29、mponents. 8 2.1Board Dimensions Table 2. Compares ATX, microATX, and Mini-ITX Board Dimensions DimensionATXmicroATXMini-ITX Maximumwidth Allowable305mm244mm170mm Maximum depth Allowable244mm244mm170mm 2.2Mounting Hole Placement Mini-ITX utilizesa subset of ATX mounting holes. To avoid damage to trac
30、es on motherboards, chassis standoffs in any locations not specified should be removable or not implemented at all. See Figure 2 for relative hole locations compared to ATX and microATX motherboards. Figure 2. ATX, microATX, and Mini-ITX Mounting Holes NOTE:Board is shown orientedwith the rear of th
31、e board towards the top. NOTE:The lighter portion indicatesthe approximate region of the Mini-ITXform factor. 9 Table 3. Motherboard Mounting Hole Locations Form FactorMounting Hole Locations Mini-ITXC,F,H,J microATXB,C,F,H,J,L,M,R,S ATXA,C,F,G,H,J,K,L,M Figure 3. Mini-ITX Board Diagram 10 2.3Connec
32、tor Placement For Mini-ITX, all connector locations as well as allowable placement area for I/O connectors on the backpanel are described and can be found in themicroATX Interface Specification. 2.3.1Thin Mini-ITX Back Panel I/O The Thin Mini-ITX Back Panel I/O area is defined in Figure 4. The width
33、 of the back panel I/O aperture and the location of the motherboard relative to the I/O aperture are the same as Mini-ITX. This allows a Thin Mini-ITX board to be used in either a Thin Mini-ITX chassis, or a Mini-ITX and larger compatible chassis when using an appropriate I/O shield. The thickness o
34、f the PCB and the topside I/O connectors shall fit within the .787” (20mm) height shown in Figure 4. Seesection 2.4.2 for additional discussion. Figure 4. Thin Mini-ITX Back Panel I/O 2.4Height Constraints 2.4.1Mini-ITX:Primary (Component)Side Height Constraints One major advantages of the Mini-ITX
35、form factor is its backward-compatibility with the ATX specification. The Mini-ITX motherboard can be installed in any ATX chassis. Figure 5 shows the required Mini-ITXmaximum component height constraintsfor the components on the PC board. For full compliance with Mini-ITX, and to prevent interferen
36、cewith the chassis structure, power supply, or peripherals, the motherboard components should not exceed the height limit in each zone defined. Similarly, compliant power supplies, peripherals, and chassis features should not extend into the motherboard component area. 11 Figure 5. Mini-ITX Maximum
37、Component Height Restrictions Notes: All dimensions in the above figure are in millimeters (mm). The57mm height restriction in Area A applies to the PC board component height. Theactual height of the chassis should include any dynamic excursion considerations for shipping as well as needs to facilit
38、ate alternativecooling solutions or airflow considerations. For the Intel boxed processor fan heat sink, it is strongly recommended not to placecomponents between fan inlet and chassis side vent by leaving space between chassis wall and area A open. Thecomponent height requirement assumes a motherbo
39、ard thickness of 1.57 mm (.062” ). 2.4.2Thin Mini-ITX:Primary (Component) Side Height Constraints Figure 6 shows the required Thin Mini-ITX volumetric envelope for the PCB and all motherboard components. For full compliance with Thin Mini-ITX, and to prevent 12 interferencewith the chassis structure
40、 and other system components, the motherboard components must not exceed the height limit in each zone defined. In Area A, the thicknessof the PCB and the topside components shall fit within the .787 ” (20mm) height shown in Figure 6. With this in mind, motherboard designers may exercise tradeoffs b
41、etween board thickness and the height of I/O components as necessary. For example, a .062” (1.57mm) PCB wouldallow.725 ” (18.43mm)for topside components, while a .093(2.3” 6mm) PCB would allow.694 ”(17.64mm). Chassis features and systemcomponents must not extend into the motherboard component area.
42、Additionally,space must be permitted around the motherboard by the chassis and other systemcomponents to allow for dynamic excursion considerations, as well as needs to facilitate alternativecooling solutions or airflow considerations. Depending on the needs of the system,components that interface w
43、ith the motherboard but are not part of it, such as a CPU heatsink, may fit within the volumetric established in Figure 6 or extend outside of it. Any components that extend through the motherboard volumetric must be selected in cooperation with the chassis to ensure there are no interference issues
44、. The motherboard may haveits own specific keep-in or keep-out requirements, such as around a CPU for its heatsink, which may also need to be considered. 13 Figure 6. Thin Mini-ITX Maximum Component Height Restrictions 2.4.3Secondary (Bottom/Solder)Side Height Constraints No height restraints on sec
45、ondary side are added or removed from what is specified in the microATX Motherboard InterfaceSpecification. 2.4.4Thin Mini-ITX SystemConsiderations While the low profile design of a Thin Mini-ITX motherboard creates the opportunity for smaller PCs, system space must be allowed for factors such as ai
46、rflow and cabling. Board headers and the cable connectors they mate to should be selected with sizeand orientation in mind. The use of tall headers which are perpendicular to the motherboard and/or long cable connectors increase the chance of interferencewith chassis components immediately overa Thi
47、n Mini-ITX board. System integration challenges can be addressed in a variety of ways, including: 14 Carefully considering venting and fan/blower strategies to ensure proper cooling can be achieved in a small chassis. Minimizing the size of board headersand cable connectors. Using board headers whic
48、h are parallel or angled to the PCB, provided sufficient spacearound and/or on the board is included in the system design for proper cable mating and connector space. 15 3Power Supply Information Provided the verydifferent needs of the platforms that fit in the small desktop form category, this spec
49、ification does not attempt to define a standard for the power supply to match with the Mini-ITX motherboard specification. Instead it recommends that manufacturers consider using a: SFX,TFX or FlexATX* are available power supply form factor for chassis greater than 4 liters. External power adapter for chassis less than 4 liters and All-in-Onedesktop PCs.* * Refer to themicroATX Motherboard Interface Specificationfor information on power supply requirements. * Refer to related systemdesign guides for information on AIO powersupply requirements. 16
