FN9256 Rev 0.00

Page 1 of 12

March 7, 2006

FN9256

Rev 0.00

March 7, 2006

ISL6273

1.2A Low Quiescent Current 1.5MHz High Efficiency Synchronous Buck Regulator

DATASHEET

ISL6273 is a 1.2A, 1.5MHz step-down regulator, which is

ideal for powering low-voltage microprocessors in compact

devices such as PDAs and cellular phones. It is optimized

for generating low output voltages down to 0.8V. The supply

voltage range is from 2.7V to 5.5V allowing the use of a

single Li+ cell, three NiMH cells or a regulated 5V input. It

has guaranteed minimum output current of 1.2A. 1.5MHz

pulse-width modulation (PWM) switching frequency allows

using small external components. It has flexible operation

mode selection of forced PWM mode and low IQ mode with

as low as 25

A quiescent current for highest light load

efficiency to maximize battery life.

The ISL6273 includes a pair of low on-resistance P-channel

and N-channel internal MOSFETs to maximize efficiency and

minimize external component count. 100% duty-cycle

operation allows less than 200mV dropout voltage at 1.2A.

The ISL6273 offers a 200ms Power-On-Reset (POR) timer

at power up. The timer output can be reset by RSI. When

shutdown, ISL6273 discharges the output capacitor. Other

features include internal digital soft-start, enable for power

sequence, overcurrent protection, and thermal shutdown.

The ISL6273 is offered in a 10 Ld 3x3mm DFN package with

1mm maximum height. The complete converter occupies

Features

• High efficiency Synchronous Buck Regulator with up to

95% Efficiency

• 200ms Reset Timer

• Discharge Output Cap when Shutdown

• 2.7V to 5.5V Supply Voltage

• 3% Output Accuracy Over Temperature/Load/Line

• 1.2A Guaranteed Output Current

•25

A Quiescent Supply Current in IQ Mode

• Selectable Forced PWM Mode and IQ Mode

• Less than 1

A Logic Controlled Shutdown Current

• 100% Maximum Duty Cycle for Lowest Dropout

• Internal Loop Compensation

• Internal Digital Soft-Start

• Peak Current Limiting, Short Circuit Protection

• Over-Temperature Protection

• Enable

• Small 10 Ld 3x3mm DFN

• Pb-Free Plus Anneal Available (RoHS Compliant)

Applications

• Single Li-Ion Battery-Powered Equipment

• DSP Core Power

• PDAs and Palmtops

Pinout

ISL6273 (10 LD 3X3 DFN)

TOP VIEW

Ordering Information

PART

NUMBER

(NOTE)

PART

MARKING

TEMP.

RANGE

(°C)

PACKAGE

(Pb-free)

PKG.

DWG. #

ISL6273IRZ

273Z

-40 to 85 10 Ld 3x3 DFN L10.3x3C

ISL6273IRZ-T 273Z

-40 to 85 10 Ld 3x3 DFN L10.3x3C

NOTE: Intersil Pb-free plus anneal products employ special Pb-free

material sets; molding compounds/die attach materials and 100%

matte tin plate termination finish, which are RoHS compliant and

compatible with both SnPb and Pb-free soldering operations. Intersil

Pb-free products are MSL classified at Pb-free peak reflow

temperatures that meet or exceed the Pb-free requirements of

IPC/JEDEC J STD-020.

PVIN

VCC

EN

POR

MODE

PHASE

PGND

SGND

FB

RSI

2

3

4

1

5

9

8

7

10

6

NOT RECOM

MENDED FO

R NEW DESIG

NS

POSSIBLE S

UBSTITUTE

PRODUCT

ISL9106