Mini-ITX Addendum to the MicroATX Specification

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” (2.36mm) PCB would allow .694” (17.64mm).

Chassis features and system components must not extend into the motherboard

component area. Additionally, space must be permitted around the motherboard by

the chassis and other system components to allow for dynamic excursion

considerations, as well as needs to facilitate alternative cooling solutions or airflow

considerations.

Depending on the needs of the system, components that interface with 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. The motherboard may have its

own specific keep-in or keep-out requirements, such as around a CPU for its heatsink,

which may also need to be considered.