LM3674

2MHz, 600mA Step-Down DC-DC Converter in SOT 23-5

General Description

The LM3674 step-down DC-DC converter is optimized for

powering low voltage circuits from a single Li-Ion cell battery

and input voltage rails from 2.7V to 5.5V. It provides up to

600mA load current, over the entire input voltage range.

There are several fixed output voltages and adjustable out-

put voltage versions.

The device offers superior features and performance for

mobile phones and similar portable systems. During PWM

mode, the device operates at a fixed-frequency of 2 MHz

(typ). Internal synchronous rectification provides high effi-

ciency during PWM mode operation. In shutdown mode, the

device turns off and reduces battery consumption to 0.01 µA

(typ).

The LM3674 is available in SOT23-5 in leaded (PB) and

lead-free (NO PB) versions. A high switching frequency of 2

MHz (typ) allows use of only three tiny external surface-

mount components, an inductor and two ceramic capacitors.

Features

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600mA max load current

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Input voltage range from 2.7V to 5.5V

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Available in fixed and adjustable output voltages ranging

from 1.0V to 3.3V

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Operates from a single Li-Ion cell Battery

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Internal synchronous rectification for high efficiency

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Internal soft start

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0.01 µA typical shutdown current

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2 MHz PWM fixed switching frequency (typ)

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SOT23-5 package

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Current overload protection and Thermal shutdown

protection

Applications

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Mobile phones

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PDAs

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MP3 players

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Portable instruments

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W-LAN

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Digital still cameras

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Portable Hard disk drives

Typical Application

20167201

FIGURE 1. Typical Application Circuit

September 2006

© 2006 National Semiconductor Corporation

DS201672

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