LM2574 datasheet(10/24 Pages) NSC

Part #	LM2574

Description	SIMPLE SWITCHER??0.5A 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 pos-

sible. Single-point grounding (as indicated) or ground plane

construction 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

DS011394-11

CIN — 22 µF, 75V

Aluminum Electrolytic

COUT — 220 µF, 25V

Aluminum Electrolytic

D1 — Schottky, 11DQ06

L1 — 330 µH, 52627

(for 5V in, 3.3V out, use

100 µH, RL-1284-100)

R1 — 2k, 0.1%

R2 — 6.12k, 0.1%

Adjustable Output Voltage Version

DS011394-12

FIGURE 2.

LM2574 Datasheet(PDF) 10 Page - National Semiconductor (TI)