1

LTC1928-5

, LTC and LT are registered trademarks of Linear Technology Corporation

ThinSOT is a trademark of Linear Technology Corporation.

FEATURES

APPLICATIO S

DESCRIPTIO

s

Low Output Noise: 90

s

Fixed Output Voltage: 5V

s

Input Voltage Range: 2.7V to 4.4V

s

No Inductors Required

s

Uses Small Ceramic Capacitors

s

Output Current Up to 30mA

s

550kHz Switching Frequency

s

Low Operating Current: 190

µA

s

Low Shutdown Current: 4

µA

s

Internal Thermal Shutdown and Current Limiting

s

Low Profile (1mm) ThinSOT

The LTC

low noise, low dropout (LDO) linear regulator. The part is

designed to provide a low noise boosted supply voltage for

powering noise sensitive devices such as high frequency

VCOs in wireless applications.

An internal charge pump converts a 2.7V to 4.4V input to

a boosted output, while the internal LDO regulator con-

verts the boosted voltage to a low noise regulated output.

The regulator is capable of supplying up to 30mA of output

current. Shutdown reduces the supply current to < 8

µA,

The LTC1928-5 LDO regulator is stable with only 2

µF on

the output. Small ceramic capacitors can be used, reduc-

ing PC board area.

The LTC1928-5 is short-circuit and overtemperature pro-

tected. The part is available in a 6-pin low profile

(1mm)ThinSOT package.

s

VCO Power Supplies for Cellular Phones

s

2-Way Pagers

s

Wireless PCMCIA Cards

s

Portable Medical Instruments

s

Low Power Data Acquisition

s

Remote Transmitters

s

White LED Drivers

s

GaAs Switches

Figure 1. Low Noise 5V Power Supply

Doubler Charge Pump with

Low Noise Linear Regulator

in ThinSOT

Output Noise (BW = 10Hz to 2.5MHz)

200

µV/DIV

19285 TA01

1

5

6

3

4

2

CPO

GND

2.7V TO 4.4V

CP

CN/SHDN

5V

4.7

µF

0.47

µF

4.7

µF

4.7

µF

19285 F01

LTC1928-5