AIC1553

Compact 500KHz PWM/PFM, Step-Down DC/DC

Converters

Analog Integrations Corporation

4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan

DS-1553-P2 061402

TEL: 886-3-5772500

FAX: 886-3-5772510

www.analog.com.tw

1

FEATURES

Tiny 5-Lead SOT-23 package

Uses Tiny Capacitors and Inductor

High Frequency Operation: 500KHz

High Output Current: 500mA

High Efficiency: Up to 90%

Current Mode Operation for Excellent Line and

Load Transient Response

Short-Circuit Protected

Low Quiescent Current: 22

µA

Low Dropout Operation: 100% Duty Cycle

Peak Inductor Current Independent of Inductor

Value

Low Output Voltages: Down to 0.75V

APPLICATIONS

Cellular Phones.

PDAs and Handy-Terminals.

CPU I/O Supplies.

Cordless Phones.

Notebook Chipset Supplies.

Handheld Equipment

DESCRIPTION

The AIC1553 is a step-down, current mode,

DC/DC converter. It operates from 2.5V to 5.5V

input voltage range and switches at 500KHz,

allowing the use of tiny, low cost capacitors and

inductors. The output voltage is adjustable from

0.75V to 5V. A built-in 0.6

Ω switch allows up to

0.5A of output current at high efficiency.

The AIC1553 operates continuously to very low

load currents to provide low ripple at the

expense of light load efficiency. With no load,

the AIC1553 draws only 22

µA. In shutdown

mode, it draws less than 1

µA, making it ideal for

current sensitive applications.

The tiny 5-lead SOT-23 package makes it

easy to save the layout area.

TYPICAL APPLICATION CIRCUIT

SW 1

GND 2

VFB 3

VIN

5

SD

4

U1

AIC1553

+ C1

10

µF

L1

6.8

µH

R2

560K

R1

240K

C2

47

µF

C3

D1

SS12

C4

4.7

µF

ON/OFF

2.5V

2.5V~5.5V

22pF

2.5V/500mA Step-Down Converter