QUK240S9R041Z Datasheet, PDF (9/14 Pages) Lineage Power Corporation – 36 - 55Vdc input; 9Vdc Output; 240W

Data Sheet
June 17, 2009
QUK240 Series Power Modules; DC-DC converters
36 – 55Vdc input; 9Vdc Output; 240W
Thermal Considerations
The power modules operate in a variety of thermal
environments and sufficient cooling should be
provided to help ensure reliable operation.
Thermal considerations include ambient temperature,
airflow, module power dissipation, and the need for
increased reliability. A reduction in the operating
temperature of the module will result in an increase in
reliability. The thermal data presented here is based
on physical measurements taken in a wind tunnel.
Heat-dissipating components are mounted on the top
side of the module. Heat is removed by conduction,
convection and radiation to the surrounding
environment. Proper cooling can be verified by
measuring the thermal reference temperatures (TH1
and TH2). Peak temperature (TH1 or TH2 ) occurs at
either of the positions indicated in Figure 13 for the
open frame power module and Figure 14 for the base
plate version. For reliable operation these
temperatures should not exceed 120 ºC for open
frame power module and 100 ºC for base plate
version of power module.
Figure 13. TH1 and H2 Temperature Measurement
Location for the QUK240S9R0 module.
Please refer to the Application Note “Thermal
Characterization Process For Open-Frame Board-
Mounted Power Modules” for a detailed discussion of
thermal aspects including maximum device
temperatures.
TH
18.5
(0.73)
29.0
(1.14)
Figure 14. Temperature Measurement Location TH1
for the base plate version of the QUK240S9R0
module.
The output power of the module should not exceed
the rated power for the module as listed in the
Ordering Information table. Although the maximum
temperature (TH1 or H2) of the power module is 120 °C,
you can limit this temperature to a lower value for
improved reliability.
Heat Transfer via Convection
Increased airflow over the module enhances the heat
transfer via convection. The derating plots in figures
15-18 show the maximum output power that can be
delivered by each module in the respective orientation
and at different ambient air temperatures without
exceeding the maximum Tref temperature. The plots
are for different airflow conditions ranging from natural
convection to 3m/s (600 ft./min).
Note that the natural convection condition was
measured at 0.05 m/s to 0.1 m/s (10ft./min. to 20
ft./min.); however, systems in which these power
modules may be used typically generate natural
convection airflow rates of 0.3 m/s (60 ft./min.) due to
other heat dissipating components in the system. The
use of Figures 15 - 18 is shown in the following
example:
Example
What is the minimum airflow necessary for a
QUK240S9R0 operating at VI = 48 V, an output
power of 240W, and a maximum ambient temperature
of 70 °C in the transverse orientation?
Solution:
Given: VI = 48V, Po = 240W, TA = 70 °C
Determine airflow (V) (Use Figure 16):
V = 1.0 m/sec. (200 ft./min.)
LINEAGE POWER
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