ALQ07 Datasheet, PDF (20/28 Pages) Astec America, Inc – Technical Reference Notes

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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 C1 can be added across the load, with a 0.1uF ceramic
capacitor C1 in parallel generally as shown in Figure ‘Output Ripple Filter for a
Distant Load’.
Decoupling
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 10uF tantalum or ceramic
capacitor in parallel with a 0.1uF 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 be
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’.
ALQ07 DC-DC Converter Technical Reference Notes
DATE: Aug., 9, 2003