1

Buck Converter

ISL9104, ISL9104A

The ISL9104, ISL9104A is a 500mA, 4.3MHz 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 6V

allowing the use of a single Li+ cell, three NiMH cells or a

regulated 5V input. It has guaranteed minimum output current

of 500mA. A high switching frequency of 4.3MHz pulse-width

modulation (PWM) allows using small external components.

mode with typical 20µA quiescent current for highest light

load efficiency to maximize battery life, and it automatically

switches to fixed frequency PWM mode under heavy load

condition.

The ISL9104, ISL9104A includes a pair of low ON-resistance

P-Channel and N-Channel internal MOSFETs to maximize

system efficiency and minimize the external component count.

100% duty-cycle operation allows less than 300mV dropout

voltage at 500mA.

The ISL9104, ISL9104A offers internal digital soft-start,

enable for power sequence, overcurrent protection and

thermal shutdown functions. In addition, the ISL9104,

ISL9104A offers a quick bleeding function that discharges the

output capacitor when the IC is disabled.

The ISL9104, ISL9104A is offered in a 1.6x1.6mm µTDFN

Applications

• Single Li-ion Battery-Powered Equipment

• Mobile Phones and MP3 Players

• PDAs and Palmtops

• WCDMA Handsets

•Portable Instruments

Features

• High Efficiency Integrated Synchronous Buck Regulator with

up to 93% Efficiency

• 2.7V to 6.0V Supply Voltage

• 4.3MHz PWM Switching Frequency

• 500mA Guaranteed Output Current

• 3% Output Accuracy Over-Temperature and Line for Fixed

Output Options

• 20µA Quiescent Supply Current in Skip Mode

• Less than 1µA Logic Controlled Shutdown Current

• 100% Maximum Duty Cycle for Lowest Dropout

• Ultrasonic Switching Frequency at Skip Mode to Prevent

Audible Frequency Noise (For ISL9104A Only)

• Discharge Output Capacitor when Disabled

• Internal Digital Soft-Start

• Peak Current Limiting, Short Circuit Protection

• Over-Temperature Protection

•Chip Enable

• Small 6 Pin 1.6mmx1.6mm µTDFN Package

• Pb-Free (RoHS Compliant)

Related Literature

• See AN1522, “ISL9104xxxxEVAL1Z, ISL9104AxxxxEVAL1Z

Evaluation Board Application Manual”

Pin Configuration

ISL9104, ISL9104A

(6 LD 1.6x1.6 µTDFN)

TOP VIEW

1

2

3

6

4

5

VIN

EN

NC

SW

GND

FB

100

95

90

85

80

75

70

65

60

55

50

1

10

100

1000

FIGURE 1. EFFICIENCY vs OUTPUT CURRENT

L = 1µH

September 21, 2011

FN6829.5

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

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