Typical Circuit and Layout Guidelines

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, the wires indicated by

heavy lines should be wide printed circuit traces and

should be kept as short as possible. For best results, ex-

ternal 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 as-

sociated wiring. Physically locate both resistors near the IC,

and route the wiring away from the inductor, especially an

open core type of inductor. (See application section for more

information.)

Fixed Output Voltage Versions

DS012439-22

D1 — 1A, 40V Schottky Rectifier, 1N5819

L1 — 100 µH, L20

Select components with higher voltage ratings for designs using the LM2594HV with an input voltage between 40V and 60V.

Adjustable Output Voltage Versions

DS012439-23

D1 — 1A, 40V Schottky Rectifier, 1N5819

L1 — 100 µH, L20

FIGURE 1. Typical Circuits and Layout Guides

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