
Lineage Power
13
Data Sheet
CC030-Series Power Modules; dc-dc Converters:
March 2008
18 Vdc to 36 Vdc Inputs, 30 W
Thermal Considerations (continued)
Heat Sink Selection
Several heat sinks are available for these modules.
The case includes through threaded mounting holes
allowing attachment of heat sinks or cold plates from
either side of the module. The mounting torque must
not exceed 0.56 N-m (5 in.-lb).
Figure
25 shows the case-to-ambient thermal resis-
tance,
θ (°C/W), for these modules. These curves can
be used to predict which heat sink will be needed for a
particular environment. For example, if the unit dissi-
pates 7.1 W of heat in an 80 °C environment with an
airflow of 0.5 ms–1 (100 ft./min.), the minimum heat
sink required can be determined as follows:
θ
TCmax
,
TA
–
() PD
≤
where:
θ
=
module's total thermal resistance
Tc, max
=
case temperature (See Figure
20.)TA
=
inlet ambient temperature
PD
=
power dissipation
θ (100 – 80)/7.1
θ 2.8 °C/W
From Figure
25, the 1/2 in. high heat sink or greater is
required.
0
0.51
(100)
1.02
(200)
2.54
(500)
3.05
(600)
0
5
6
7
8
AIR VELOCITY, ms
–1 (ft./min.)
4
3
2
1
1.52
(300)
2.03
(400)
NO HEAT SINK
1/4 in. HEAT SINK
1/2 in. HEAT SINK
1 in. HEAT SINK
8-1157(C).c
Figure 25. Case-to-Ambient Thermal Resistance
vs. Air Velocity Curves; Either
Orientation
Although the previous example uses 100 °C as the
maximum case temperature, for extremely high-reliabil-
ity applications, one can use a lower temperature for
Tc, max.
It is important to point out that the thermal resistances
shown in Figure
25 are for heat transfer from the sides
and bottom of the module as well as the top side with
the attached heat sink; therefore, the case-to-ambient
thermal resistances shown will generally be lower than
the resistance of the heat sink by itself. The data in Fig-
ure
25 was taken with a thermally conductive dry pad
between the case and the heat sink to minimize contact
resistance (typically 0.1 °C/W to 0.3 °C/W).
For a more detailed explanation of thermal energy
management for this series of power modules as well
as more details on available heat sinks, please request
the following technical note: Thermal Energy Manage-
ment CC-, CW-, DC-, and DW-Series 25 W to 30 W
Board-Mounted Power Modules (TN97-015EPS).
Layout Considerations
Copper paths must not be routed beneath the power
module standoffs.