LAYOUT SUGGESTIONS

As in any switching regulator, layout is very important. Rap-

idly switching currents associated with wiring inductance can

generate voltage transients which can cause problems. For

minimal inductance and ground loops, with reference to

Figure 1, the wires indicated by heavy lines should be wide

printed circuit traces and should be kept as short as

possible. For best results, external components should be

located as close to the switcher lC as possible using ground

plane construction or single point grounding.

If open core inductors are used, special care must be

taken as to the location and positioning of this type of induc-

tor. Allowing the inductor flux to intersect sensitive feedback,

lC groundpath and C

When using the adjustable version, special care must be

taken as to the location of the feedback resistors and the

associated wiring. Physically locate both resistors near the

IC, and route the wiring away from the inductor, especially an

open core type of inductor.

10129342

FIGURE 12. Inverting Regulator Ground Referenced Shutdown

10129386

FIGURE 13. Inverting Regulator Ground Referenced Shutdown using Opto Device

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