Mini-ITX Addendum Version 2.0 To the microATX Motherboard Interface Specification Version 1.
1. INTEL CORPORATION (“INTEL”) MAKES NO WARRANTIES WITH REGARD TO THIS SPECIFICATION (“SPECIFICATION”), AND IN PARTICULAR DOES NOT WARRANT OR REPRESENT THAT THIS SPECIFICATION OR ANY PRODUCTS MADE IN CONFORMANCE WITH IT WILL WORK IN THE INTENDED MANNER.
Contents Revision History..................................................................................................................... 4 1 Executive Summary ........................................................................................... 5 1.1 1.2 1.3 1.4 2 6 6 6 6 Layout .............................................................................................................. 8 2.1 2.2 2.3 2.4 3 Terminology .......................................................................
Revision History Revision Number Description Revision Date 2.0 Added Thin Mini-ITX definition. Oct, 2010 1.1 Minor corrections made. Title changed to: Feb, 2009 ‘Mini-ITX Addendum Version 1.1 To the microATX Motherboard Interface Specification Version 1.2’ to reflect full name of mATX document name. 1.0 Initial release.
1 Executive Summary The Mini-ITX addendum to the microATX Motherboard Interface Specification details the use the Mini-ITX form factor standard, developed by Via Technologies Inc, for compatibility with Intel based platforms. This document defines only the specific features in Intel’s Mini-ITX based platforms that differ from those of microATX and should be used in conjunction with the governing microATX specification.
The Mini-ITX Addendum To the microATX Motherboard Interface Specification is 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 1.1 Terminology Term 1.
compatibility between their products. They can 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, multi-core processors. It eliminates the need for them to design targeted chassis for each platform.
2 Layout 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 constraints are specified. System components such as hard drives, disk drives, and power supplies are not specified; however, it is generally recommended 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.
2.1 Board Dimensions Table 2. Compares ATX, microATX, and Mini-ITX Board Dimensions 2.2 Dimension ATX microATX Mini-ITX Maximum width Allowable 305mm 244mm 170mm Maximum depth Allowable 244mm 244mm 170mm Mounting Hole Placement Mini-ITX utilizes a subset of ATX mounting holes. To avoid damage to traces on motherboards, chassis standoffs in any locations not specified should be removable or not implemented at all.
Table 3. Motherboard Mounting Hole Locations Form Factor Mounting Hole Locations Mini-ITX C,F,H,J microATX B,C,F,H,J,L,M,R,S ATX A,C,F,G,H,J,K,L,M Figure 3.
2.3 Connector Placement For Mini-ITX, all connector locations as well as allowable placement area for I/O connectors on the back panel are described and can be found in the microATX Interface Specification. 2.3.1 Thin Mini-ITX Back Panel I/O The Thin Mini-ITX Back Panel I/O area is defined in Figure 4. The width 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.
Figure 5. Mini-ITX Maximum Component Height Restrictions Notes: 2.4.2 All dimensions in the above figure are in millimeters (mm). The 57mm height restriction in Area A applies to the PC board component height. The actual height of the chassis should include any dynamic excursion considerations for shipping as well as needs to facilitate alternative cooling solutions or airflow considerations.
interference with the chassis structure and other system components, the motherboard components must not exceed the height limit in each zone defined. In Area A, the thickness of 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 between board thickness and the height of I/O components as necessary. For example, a .062” (1.57mm) PCB would allow .725” (18.43mm) for topside components, while a .093” (2.
Figure 6. Thin Mini-ITX Maximum Component Height Restrictions 2.4.3 Secondary (Bottom/Solder) Side Height Constraints No height restraints on secondary side are added or removed from what is specified in the microATX Motherboard Interface Specification. 2.4.4 Thin Mini-ITX System Considerations 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 airflow and cabling.
Carefully considering venting and fan/blower strategies to ensure proper cooling can be achieved in a small chassis. Minimizing the size of board headers and cable connectors. Using board headers which are parallel or angled to the PCB, provided sufficient space around and/or on the board is included in the system design for proper cable mating and connector space.
3 Power Supply Information Provided the very different needs of the platforms that fit in the small desktop form category, this specification 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-One desktop PCs.
