modules with high power AFT modules, the
option to bring in air from both card edges
and exhaust it out of the top, becomes very
The VITA 48.8 spec also encourages certain
weight and power savings that drive a self-
improving process where each variable feeds
into the other. For example, removing parts
such as a retainer and jack screws in turn
saves weight and space. Not having to use a
retainer also means there is no parallel heat
path of conduction into the chassis, which
allows for weight reduction in the chassis
itself. This means that the chassis doesn’t have
to be metal or another thermally conductive
material. Instead, it can be made out of
composite materials or 3D printed plastic.
At VITA, Curtiss-Wright demonstrated a
3D-printed plastic chassis for 3U modules.
The only metal used in the chassis is on the
AFT thermal frames, since it was not strictly
required anywhere else.
Like Gipper, Straznicky says that the most
pressing challenge in thermal management is
keeping up with the power density on some
processors. AFT makes that easier, as does
combining AFT with affordable thermal interface
materials and heat spreader approaches.
“For example, thermal interface materials
and heat spreaders have to be looked at and
optimized,” Straznicky says. “By bringing AFT
into the equation, that optimization exercise
becomes easier and allows you to use
affordable technologies and materials along
the thermal transfer path, allowing you to
avoid more exotic and expensive alternatives.”
VITA 48.8 needs to go into an American
National Standards Institute ballot before it is
available for the public. If approved, it will be
an IP-free standard, with no licensing required.
Curtiss-Wright is also keeping an eye on
VITA’s next liquid flow through (LFT) standard,
which could be used for extremely high power
modules and systems that require even more
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robust cooling than AFT technologies can supply. People will also be looking
to VITA 48.4, the LFT standard, as a possible upgrade solution for existing LFT
systems, Straznicky says.
Gipper doesn’t foresee any massive changes in embedded tech standards by
the time VITA holds its conference next year. However, he does expect some
more conversation about liquid cooling, including the basic physical challenges
of putting a computer inside a box that also contains liquid. Some elements
of thermal management will take place at the level of the transistors and
We’ll see next year, but for now, bus and board designers are working on
using VITA standards to support better thermal management.
The 3U AFT chassis is designed in accordance with VITA 48.8
standards for optimum air flow. Image credit: Curtiss-Wright