MHST02525 Lineage Power, MHST02525 Datasheet - Page 3

• Manufacturer Part Number: MHST02525
• Description: HEATSINK 1.48L X.225"H EXTRUSION
• Manufacturer: Lineage Power

Specifications of MHST02525

• Attachment Method: Bolt On
• Outline: 37.60mm x 36.80mm
• Height: 0.225" (5.715mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Package Cooled: -
• Power Dissipation @ Temperature Rise: -
• Thermal Resistance @ Forced Air Flow: -
• Thermal Resistance @ Natural: -

Technical Note
July 1996
Module Derating
Convection Without Heat Sinks
Increasing airflow over the module enhances heat
transfer via convection. Figures 4 and 5 show the maxi-
mum power that can be dissipated by the module with-
out exceeding the maximum case temperature versus
local ambient temperature (T
through 800 ft./min. A natural convection condition is
produced when air is moved only through the buoyancy
effects produced by a temperature gradient between
the module and surrounding air. In the test setup used,
natural convection airflow was measured at 10 ft./min.
to 20 ft./min., whereas systems in which these power
modules may be used typically generate natural con-
vection airflow rates of 60 ft./min. due to other heat dis-
sipating components in the system. The 100 ft./min. to
800 ft./min. curves are for airflow added externally to
the test setup, usually through the use of fans. Note
that there is a thermal performance improvement when
the long axis of the module is perpendicular to the air-
flow direction (transverse orientation).
Tyco Electronics Corp.
Figure 4. Convection Power Derating with No
70
60
50
40
30
20
10
0
0
20 ft./min. (NAT. CONV.)
10
Heat Sink; Airflow Along Length (Lon-
gitudinal)
LOCAL AMBIENT TEMPERATURE, T
20
30
(continued)
40
A
) for natural convection
50
60
70
800 ft./min.
700 ft./min.
600 ft./min.
500 ft./min.
400 ft./min.
300 ft./min.
200 ft./min.
100 ft./min.
A
80
( C)
90
100
8-1314
250 W—300 W Board-Mounted Power Modules
Thermal Management for FC- and FW-Series
Figures 4 and 5 can be used to determine the appropri-
ate airflow for a given set of operating conditions as
shown in the following examples.
Example 1: Airflow Required to Maintain Tc
What is the minimum airflow necessary for a FW300A1
in the transverse orientation, operating at 54 V input, an
output current of 50 A, and a maximum ambient tem-
perature of 35 °C?
Solution:
Example 2: Maximum Power Output
What is the maximum power output for a FW300A1 in
the longitudinal orientation, operating at 54 V input, in
an environment that provides 600 ft./min. with a maxi-
mum ambient temperature of 40 °C?
Solution:
Although the above two examples use 100 °C as the
operating case temperature, for extremely high reliabil-
ity applications, one may design to a lower case tem-
perature as shown later in Example 4.
Given: V
Determine P
Determine Airflow (Figure 5): v = 800 ft./min.
Given: V
Determine P
Determine Io (Figure 2): Io = 40 A
Calculate Po = (Vo) * (Io) = 5 x 40 = 200 W
Figure 5. Convection Power Derating with No
70
60
50
40
30
20
10
0
0
20 ft./min. (NAT. CONV.)
I
I
= 54 V, v = 600 ft./min., T
= 54 V, Io = 50 A, T
10
Heat Sink; Airflow Along Width (Trans-
verse)
LOCAL AMBIENT TEMPERATURE, T
D
D
20
(Figure 2): P
(Figure 4): P
30
40
D
D
50
A
= 46 W
= 34 W
= 35 °C
60
A
= 40 °C
70
800 ft./min.
700 ft./min.
600 ft./min.
500 ft./min.
400 ft./min.
300 ft./min.
200 ft./min.
100 ft./min.
A
80
( C)
90
8-1315
100
3