Thermal Considerations - Sierra Wireless MC5725 Hardware Integration Manual

6: Thermal Considerations

Rev 1.9.1 Feb.09
In the event of a discrepancy in values between this guide and the Product Specification Document (PSD), the PSD takes precedence.
This chapter describes the thermal characteristics of the
module and provides suggestions for testing and addressing
thermal issues.
Thermal considerations
Mini Cards can generate significant amounts of heat that must
be dissipated in the host device for safety and performance
reasons.
The amount of thermal dissipation required depends on the
following factors:
Supply voltage — Maximum power dissipation for these
•
modules can be up to 3.1 W at voltage supply limits.
• Usage — Typical power dissipation values depend on the
location within the host, amount of data transferred, etc.
Specific areas requiring heat dissipation include the four shield
cases indicated in Figure 6‐1.
Transmitter—top shield (next to RF connectors). This is
•
likely to be the hottest area.
Baseband 1—bottom shield, below the transmitter
•
Receiver—top shield, other side of module from the trans‐
•
mitter
• Baseband 2—bottom shield, below the receiver
You can enhance heat dissipation by:
• Maximizing airflow over / around the module
Locating the module away from other hot components
•
Note: Adequate dissipation of heat is necessary to ensure that the
module functions properly, and to comply with the thermal require-
ments in PCI Express Mini Card Electromechanical Specification
Revision 1.1.
Module testing
When testing your integration design:
• Test to your worst case operating environment conditions
(temperature and voltage)
• Test using worst case operation (transmitter on 100% duty
cycle, maximum power)
Monitor temperature at all shield locations. Attach thermo‐
•
couples to each shield indicated below
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