AIF25R48_03 Datasheet, PDF (19/29 Pages) Astec America, Inc – Isolated DC/DC Converter Module

AIF25R48 Series Technical Reference Note
Fig.7 Output Ripple Filter
Extra care should be taken when long leads or traces are used to provide power to the load.
Long lead lengths increase the chance for noise to appear on the lines. Under these
conditions C2 can be added across the load, with a 0.47F ceramic capacitor C2 in parallel
generally as shown in Figure ‘Output Ripple Filter for a Distant Load’.
Decoupling
Fig.8 Output Ripple Filter for a Distant Load
Noise on the power distribution system is not always created by the converter. High speed
analog or digital loads with dynamic power demands can cause noise to cross the power
inductor back onto the input lines. Noise can be reduced by decoupling the load. In most
cases, connecting a 10F tantalum or ceramic capacitor in parallel with a 0.1F ceramic
capacitor across the load will decouple it. The capacitors should be connected as close to
the load as possible.
Ground Loops
Ground loops occur when different circuits are given multiple paths to common or earth
ground, as shown in Figure ‘Ground Loops’. Multiple ground points can slightly different
potential and cause current flow through the circuit from one point to another. This can result
in additional noise in all the circuits. To eliminate the problem, circuits should be designed
with a single ground connection as shown in Figure ‘Single Point Ground’.
DATE: May 28, 2003
MODEL : AIF25R48 SERIES
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