3.1 Output current derating
■
The TUNS300/500/700 series should be conduction-cooled.
■
Fig.3.1, Fig.3.2 and Fig.3.3 show the derating curve in relation to the temperature of
the aluminum base plate.
Note that operation within the shaded area will cause a significant level of ripple and
ripple noise.
■
Please measure the temperature of the aluminum base plate at the center.
Please measure the temperature on the aluminum base plate edge side when you cannot
measure the temperature of the center part of the aluminum base plate.
In this case, please take 5deg temperature margin from the derating characteristics
shown in Fig.3.1, Fig.3.2 and Fig.3.3.
■
■
Attention should be paid to thermal fatigue life due to temperature fluctuations by
self-heating. Make the range of temperature fluctuations as narrow as possible if
temperature often fluctuates.
Fig.3.1
TUNS300F
Output current
derating
Fig.3.2
TUNS500F
Output current
derating
Fig.3.3
TUNS700F
Output current
derating
A-8
In the case of forced air cooling, please measure the temperature on the aluminum base plate
edge side of the leeward side. Especially in the case of small heat sink, the temperature
difference between the base plate center and the base plate edge side will increase. In this case,
the temperature margin of 5deg is not required.
Aluminum base plate temperature Tc [℃]
Lo
ad
f
ac
to
r[
%]
-40
-20
0
20
40
60
100
80
(75)
100
50
0
(75)
-40
-20
0
20
40
60
100
80
(75)
100
50
0
(70)
①TUNS700F12
②TUNS700F28,TUNS700F48
①
②
Aluminum base plate temperature Tc [℃]
Lo
ad
f
ac
to
r[
%]
Aluminum base plate temperature Tc [℃]
Lo
ad
f
ac
to
r[
%]
-40
-20
0
20
40
60
100
80
100
50
0
Tc
Measuring
point
Base plate
2.1 Pin configuration
3. Derating
①TUNS500F12
②TUNS500F28,TUNS500F48
①
②
Applications Manual
TUNS300/500/700
