1

LTC1682/LTC1682-3.3/LTC1682-5

Doubler Charge Pumps with

Low Noise Linear Regulator

s

Low Output Noise: 60

s

Adjustable or Fixed Boosted Output

s

Adjustable Output Voltage Range: 2.5V to 5.5V

s

Fixed Output Voltages: 3.3V, 5V

s

Wide Input Voltage Range: 1.8V to 4.4V

s

Uses Small Ceramic Capacitors

s

No Inductors Required

s

Output Current up to 50mA

s

550kHz Switching Frequency

s

Low Operating Current: 150

µA

s

Low Shutdown Current: 1

µA

s

Internal Thermal Shutdown and Current Limiting

s

Available in 8-Pin MSOP and SO Packages

The LTC

pumps with an internal low noise, low dropout (LDO) linear

regulator. These parts are designed to provide a low noise

boosted supply voltage for powering noise sensitive devices

such as high frequency VCOs in wireless applications.

An internal doubler charge pump converts a 1.8V to 4.4V

input to a boosted output, while the internal LDO regulator

converts the boosted voltage to a low noise regulated output.

resistors connected to FB. The regulator is capable of supply-

ing up to 50mA of output current. Shutdown reduces the

supply current to < 5

through a 100

Ω switch.

The LTC1682 LDO regulator is stable with only 2

µF on the

output. Small ceramic capacitors can be used, reducing PC

board area.

The LTC1682/LTC1682-3.3/LTC1682-5 are short-circuit and

over temperature protected. The parts are available in 8-pin

MSOP and SO packages.

, LTC and LT are registered trademarks of Linear Technology Corporation.

Open-Loop Close-In Phase Noise

CENTER = 902MHz

RES BW = 1kHz

SPAN = 100kHz

VBW = 30Hz

SWP = 10 sec

REF = 0dBm

1682 TA02

s

VCO Power Supplies in Cellular Phones

s

2-Way Pagers

s

Wireless PCMCIA Cards

s

Portable Medical Instruments

s

Low Power Data Acquisition

s

Remote Transmitters

AMPLITUDE

10dB/DIV

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

36k

SHUTDOWN

15k

100k

4.7

µF

0.22

µF

2.5V TO

4.4V

4.7

µF

4.2V

1

2

3

4

8

7

6

5

SHDN

FB

GND

CPO

1682 TA01

LTC1682

VCO

MURATA

MQE001-902

1

µF

4.7

µF 1000pF

1k

B

M

P

C

1000pF

1000pF

4.7

µF

902MHz