Datasheet

Advance Data Sheet: iAF Series – Non-isolated SMT Power Module
©2011 TDK Innoveta Inc.
iAF12_Full_Datasheet_10032012.doc 10/3/2012
℡
(877) 498
-
0099
14/18
Thermal Management:
An important part of the overall system design process
is thermal management; thermal design must be
considered at all levels to ensure good reliability and
lifetime of the final system. Superior thermal design
and the ability to operate in severe application
environments are key elements of a robust, reliable
power module.
A finite amount of heat must be dissipated from the
power module to the surrounding environment. This
heat is transferred by the three modes of heat
transfer: convection, conduction and radiation. While
all three modes of heat transfer are present in every
application, convection is the dominant mode of heat
transfer in most applications. However, to ensure
adequate cooling and proper operation, all three
modes should be considered in a final system
configuration.
The open frame design of the power module provides
an air path to individual components. This air path
improves convection cooling to the surrounding
environment, which reduces areas of heat
concentration and resulting hot spots.
Test Setup:
The thermal performance data of the
power module is based upon measurements obtained
from a wind tunnel test with the setup shown in the
wind tunnel figure. This thermal test setup replicates
the typical thermal environments encountered in most
modern electronic systems with distributed power
architectures. The electronic equipment in
networking, telecom, wireless, and advanced
computer systems operates in similar environments
and utilizes vertically mounted PCBs or circuit cards in
cabinet racks.
The power module, as shown in the figure, is mounted
on a printed circuit board (PCB) and is vertically
oriented within the wind tunnel. The cross section of
the airflow passage is rectangular. The spacing
between the top of the module and a parallel facing
PCB is kept at a constant (0.5 in). The power
module’s orientation with respect to the airflow
direction can have a significant impact on the
module’s thermal performance.
Thermal Derating
: For proper application of the
power module in a given thermal environment, output
current derating curves are provided as a design
guideline on the Thermal Performance section for the
power module of interest. The module temperature
should be measured in the final system configuration
to ensure proper thermal management of the power
module. For thermal performance verification, the
module temperature should be measured at the
component indicated in the thermal measurement
location figure on the thermal performance page for
the power module of interest. In all conditions, the
power module should be operated below the
maximum operating temperature shown on the
derating curve. For improved design margins and
enhanced system reliability, the power module may be
operated at temperatures below the maximum rated
operating temperature
.
Heat transfer by convection can be enhanced by
increasing the airflow rate that the power module
experiences. The maximum output current of the
power module is a function of ambient temperature
(T
AMB
) and airflow rate as shown in the thermal
performance figures on the thermal performance page
for the power module of interest. The curves in the
figures are shown for natural convection through 2 m/s
(400 ft/min). The data for the natural convection
condition has been collected at 0.3 m/s (60 ft/min) of
airflow, which is the typical airflow generated by other
heat dissipating components in many of the systems
that these types of modules are used in. In the final
system configurations, the airflow rate for the natural
convection condition can vary due to temperature
gradients from other heat dissipating components.
AIRFLOW
Air Velocity and Ambient Temperature
Measurement Location
A
I
R
F
L
O
W
12.7
(0.50)
Module
Centerline
Air Passage
Centerline
Adjacent PCB
76 (3.0)
Wind Tunnel Test Setup Figure
Dimensions are in
millimeters and (inches).