FEB 14, 2006 revised to MAY 17, 2006 Page 11 of 14 www.power-one.com
HKS48T30120 DC-DC Series Data Sheet
Half-Brick with 48VDC Input; 12VDC @ 32A Output
Application Information
+Vout
-Vout-Vin
+Vin
N/C
c
Fuse
C1
C2
4
ON/
OFF
c
3
2
1
9
5
+Sen
Trim
-Sen
8
7
6
Figure 16. Recommended Connections for the HKS Converter
It is strongly advisable to install external capacitors at
the input
(C1) and output (C2) of the HKS converter as
shown above. These should be of suitably high
quality and rated for effective use at low
temperatures as needed. If the distribution of the
input voltage to the converter contains significant
inductance, additional capacitance at C1 may be
required to guarantee full performance.
Ref. Des Minimum recommendations
C1
100 µF, ESR < 100 mOhms
1
C2
220 µF, 35 < ESR < 70 mOhms
1
1
Tantalum, aluminum electrolytic or (OS-CON) aluminum
semiconductor electrolyte types appropriately rated to the
required operating voltage and temperature.
Inrush Current
Refer to the “Inrush Current Control Application Note”
(http://www.power-one.com/technical/articles/dc-
dc_1-app.pdf) for suggestions on how to limit the
magnitude of the inrush current.
Thermal Considerations
HKS converters are designed for both natural and
forced convection cooling. To achieve long term
reliability, the recommended power derating curves
below, were established by comparing measured
junction and hot spot temperatures against those
allowed per Power-One’s component derating
guidelines
The graph in Figure 17 shows the maximum
recommended output current of the HKS converter at
various ambient temperatures under both natural and
forced convection (longitudinal airflow direction, from
pin 1 to pin 4). Vin = 48 VDC.
0
4
8
12
16
20
24
28
32
25 40 55 70 85
Ambient Temperature (Deg C)
Load Current (A)
NC (25 - 35 LFM) 100 LFM 200 LFM 300 LFM 400 LFM
Figure 17. HKS Power Derating Curves
Example, from above, HKS operating at 70°C can
deliver up to 20.5Amps reliably with 200LFM of forced
air applied.
Thermal Measurements
Measurements requiring airflow were made in Power-
One’s vertical wind tunnel equipment using both
Infrared (IR) thermography as well as the traditional
thermocouple method.
With the converter installed into the host application,
customer verification that all components are at or
below their safe operating temperatures may be
performed similarly. However, for a more simplified
testing method, monitoring the converter’s designated
thermal reference point(s) will yield effective results.
Refer to Figure 18 & 19 for recommended location of
the measuring thermocouple. This reference point
should be maintained at <
124
°
C.
