lm2595sx-adj National Semiconductor Corporation, lm2595sx-adj Datasheet - Page 8

• Manufacturer Part Number: lm2595sx-adj
• Description: Simple Switcher Power Converter 150 Khz 1a Step-down Voltage Regulator
• Manufacturer: National Semiconductor Corporation

www.national.com
Test Circuit and Layout Guidelines
C
C
D1 — 3A, 40V Schottky Rectifier, 1N5822
L1 — 100 µH, L29
C
C
D1 — 3A, 40V Schottky Rectifier, 1N5822
L1 — 100 µH, L29
R
C
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.
IN
OUT
IN
OUT
1
FF
— 1 k , 1%
— 120 µF, 50V, Aluminum Electrolytic Nichicon “PL Series”
— 120 µF, 50V, Aluminum Electrolytic Nichicon “PL Series”
— See Application Information Section
— 120 µF, 25V Aluminum Electrolytic, Nichicon “PL Series”
— 120 µF, 25V Aluminum Electrolytic, Nichicon “PL Series”
FIGURE 1. Standard Test Circuits and Layout Guides
Adjustable Output Voltage Versions
Fixed Output Voltage Versions
8
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.)
OUT
wiring can cause problems.
DS012565-23
DS012565-22