Datasheet

Data Sheet
©2013
Würth Elektronik eiSos GmbH & Co. KG - REV 0.2
PRELIMINARY
13/ 23
171020601/WPMDH1200601J
MagI³C Power Module Product Family
VDRM - Variable Step Down Regulator Module
J CIRCUIT DESCRIPTION
0.0
0.4 0.8
1.2
1.6
2.0
0.0
1.8
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
Power Loss [W]
Output Current [A]
Power Loss: V
IN
= 24V @ T
AMB
= 85°C
V
OUT
= 3.3V
V
OUT
= 2.5V
V
OUT
= 1.8V
V
OUT
= 5.0V
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. In order to estimate the necessary copper area
we can refer to the following package thermal resistance graph. This graph is taken from the typical performance
characteristics section and shows how the 

varies with the PCB area.
Thermal Resistance θ
JA
[°C/W]
Board Area [cm²]
Package Thermal Resistance θ
JA
4 Layer
Printed Circuit Board with 35µm Copper
0LFM (0m/s) air
225LFM (1.14m/s) air
500LFM (2.54m/s) air
Evaluation Board Area
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60
For 

  and only natural convection (i.e. no air flow), the PCB area can be smaller than 12cm
2
. This
corresponds to a square board with 3cm x 3cm 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.
PCB Layout Instructions:
PC board layout is an important part of DC-DC converter design. Poor board layout can disrupt the performance of a
DC-DC converter and surrounding circuitry by contributing to EMI, ground bounce and resistive voltage drop in the
traces. These can send erroneous signals to the DC-DC converter resulting in poor regulation or instability. Good
layout can be implemented by following five simple design rules.