Kontron COMe-cPV2(v1.4) - Manual (Page 56)

Kontron microETXexpress-PV User’s Guide
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6 Design Considerations
6.1 Thermal Management
A heat spreader plate assembly is available from Kontron Embedded Modules for
the microETXexpress®-PV COM. The heat spreader plate on top of this assembly
is NOT a heat sink. It works as a COM Express®-standard thermal interface to
be used with a heat sink or other cooling device.
External cooling must be provided to maintain the heat spreader plate at
proper operating temperatures. Under worst-case conditions, the cooling
mechanism must maintain an ambient air and heat spreader plate temperature of
60° C or less.
The aluminum slugs and thermal pads on the underside of the heat spreader
assembly implement thermal interfaces between the heat spreader plate and the
major heat-generating components on the microETXexpress®-PV. About 80 percent
of the power dissipated within the module is conducted to the heat spreader
plate and can be removed by the cooling solution.
Kontron also has defined a passive heat sink that can be used in place of the
heat spreader plate to provide additional cooling. You can use many thermal-
management solutions with the heat spreader plates, including active and
passive approaches. The optimum cooling solution varies, depending on the COM
Express® application and environmental conditions. Drawings for both the heat
spreader plate and the passive heat sink are available on request. Also, see
the PICMG COM Express® Design Guide on the PICMG website for further
information about thermal management.
6.2 Heat Spreader Dimensions
Documentation for the microETXexpress®-PV COM heat spreader and cooling
solutions is provided at
http://emdcustomersection.kontron.com .
6.3 Onboard Fan Connector
This section describes how to connect an optional fan to the connector
located directly on the microETXexpress®-PV COM. With certain BIOS-settings
it is possible to control the fan depending on the active trip point
temperature. The fan switches on/off depending on the adjusted Active Trip
Point temperature. This feature requires an ACPI-compliant OS to function
properly. The fan PWM control is done on the GND pin rather than the positive
side. Please do not use pin 3 as a ground connection. See schematic below for
more details.