LM2665

Switched Capacitor Voltage Converter

General Description

The LM2665 CMOS charge-pump voltage converter oper-

ates as a voltage doubler for an input voltage in the range of

+2.5V to +5.5V. Two low cost capacitors and a diode

(needed during start-up) are used in this circuit to provide up

to 40 mA of output current. The LM2665 can also work as a

voltage divider to split a voltage in the range of +1.8V to

+11V in half.

The LM2665 operates at 160 kHz oscillator frequency to re-

duce output resistance and voltage ripple. With an operating

current of only 650 µA (operating efficiency greater than 90%

with most loads) and 1µA typical shutdown current, the

LM2665 provides ideal performance for battery powered

systems. The device is in SOT-23-6 package.

Features

n Doubles or Splits Input Supply Voltage

n SOT23-6 Package

n 12

Ω Typical Output Impedance

n 90% Typical Conversion Efficiency at 40 mA

n 1µA Typical Shutdown Current

Applications

n Cellular Phones

n Pagers

n PDAs

n Operational Amplifier Power Suppliers

n Interface Power Suppliers

n Handheld Instruments

Basic Application Circuits

Voltage Doubler

DS100049-1

Splitting V

DS100049-2

November 1999

© 1999 National Semiconductor Corporation

DS100049

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