Datasheet
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© May 2016
Würth Elektronik eiSos GmbH & Co. KG - Data Sheet - REV 1.0
36/46
WPMDU1251501 / 171021501
MagI³C Power Module
VDRM - Variable Step Down Regulator Module
06D
Power Loss [W]
Output Current [A]
Power Loss: V
IN
= 24V @ T
AMB
= 25°C
0
0.5
1.0 1.5 2.0 2.5
0
1
2
3
4
5
6
V
OUT
= 5.0V, f
SW
= 500 kHz
V
OUT
= 3.3V, f
SW
= 400 kHz
V
OUT
= 2.5V, f
SW
= 400 kHz
V
OUT
= 12V, f
SW
= 800 kHz
V
OUT
= 15V, f
SW
= 1000 kHz
From the graph we read a power loss of 1.5W. Adding 20% results in a loss of 1.8W. Entering the values in formula (16)
results in:
To achieve this thermal resistance the PCB is required to dissipate the heat effectively. The area of the PCB will have a
direct effect on the overall junction-to-ambient thermal resistance.
For
and only natural convection (i.e. no air flow), the minimum PCB area should be slightly smaller than
60cm
2
. This corresponds to a square board with 7,6 cm x 7,6 cm copper area, 4 layers, and 35µm copper thickness. Higher
copper thickness will further improve the overall thermal performance. Note that thermal vias should be placed under the
IC package to easily transfer heat from the top layer of the PCB to the inner layers and the bottom layer.