LM2576 datasheet(10/24 Pages) NSC

Part #	LM2576

Description	SIMPLE SWITCHER 3A Step-Down Voltage Regulator

PDF	24 Pages

Scroll/Zoom	100%

Manufacturer	NSC [National Semiconductor (TI)]

Direct Link	http://www.national.com

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10 / 24 page

Test Circuit and Layout Guidelines

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

idly switching currents associated with wiring inductance

generate voltage transients which can cause problems. For

minimal inductance and ground loops, the length of the leads

indicated by heavy lines should be kept as short as possible.

Single-point grounding (as indicated) or ground plane con-

struction should be used for best results. When using the

Adjustable version, physically locate the programming resis-

tors near the regulator, to keep the sensitive feedback wiring

short.

Fixed Output Voltage Versions

01147607

CIN — 100 µF, 75V, Aluminum Electrolytic

COUT — 1000 µF, 25V, Aluminum Electrolytic

D1 — Schottky, MBR360

L1 — 100 µH, Pulse Eng. PE-92108

R1 — 2k, 0.1%

R2 — 6.12k, 0.1%

Adjustable Output Voltage Version

01147608

where VREF = 1.23V, R1 between 1k and 5k.

FIGURE 2.

LM2576 Datasheet(PDF) 10 Page - National Semiconductor (TI)