LM2685

Dual Output Regulated Switched Capacitor Voltage

Converter

General Description

The LM2685 CMOS charge-pump voltage converter oper-

ates as an input voltage doubler, +5V regulator and inverter

for an input voltage in the range of +2.85V to +6.5V. Five low

cost capacitors are used in this circuit to provide up to 50mA

LM2685 operates at a 130 kHz switching frequency to re-

duce output resistance and voltage ripple. With an operating

current of only 800µA (operating efficiency greater than 80%

with most loads) and 6µA typical shutdown current, the

LM2685 is ideal for use in battery powered systems. The de-

vice is in a small 14-pin TSSOP package.

Features

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+5V regulated output

n

Inverts V

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Doubles input supply voltage

n

TSSOP-14 package

n

80% typical conversion efficiency at 25mA

n

Input voltage range of 2.85V to 6.5V

n

Independent shutdown control pins

Applications

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Cellular phones

n

Pagers

n

PDAs

n

Handheld instrumentation

n

3.3V to 5V voltage conversion applications

Typical Application and Connection Diagram

Ordering Information

Order Number

Package Type

NSC Package

Drawing

Supplied As

LM2685MTC

TSSOP-14

MTC14

94 Units, Rail

LM2685MTCX

TSSOP-14

MTC14

2.5k Units, Tape and Reel

DS101100-1

DS101100-2

14-Pin TSSOP

May 2000

© 2000 National Semiconductor Corporation

DS101100

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