General Description

The MAX8621Y/MAX8621Z power-management inte-

grated circuits (PMICs) are designed for a variety of

portable devices including cellular handsets. These

PMICs include two high-efficiency step-down DC-DC

converters, four low-dropout linear regulators (LDOs)

with pin-programmable capability, one open-drain dri-

ver, a 60ms (typ) reset timer, and power-on/off control

logic. These devices offer high efficiency with a no-load

supply current of 160µA, and their small thin QFN 4mm

x 4mm package makes them ideal for portable devices.

The step-down DC-DC converters utilize a proprietary

4MHz hysteretic-PWM control scheme that allows for

ultra-small external components. Internal synchronous

rectification improves efficiency and eliminates the

external Schottky diode that is required in conventional

step-down converters. The output voltage is adjustable

from 0.6V to 3.3V. The output current is guaranteed up

to 500mA.

dropout of only 100mV at 100mA. OUT1 and OUT2

deliver 300mA (min) of continuous output current.

OUT3 and OUT4 deliver 150mA (min) of continuous

output current. The output voltages are pin selectable

by SEL1 and SEL2 for flexibility. The MAX8621Y/

MAX8621Z offer different sets of LDO output voltages.

A microprocessor reset output (

RESET) monitors OUT1

and warns the system of impending power loss, allow-

ing safe shutdown.

RESET asserts during power-up,

power-down, shutdown, and fault conditions where

A 200mA driver output is provided to control LED back-

lighting or provide an open-drain connection for resis-

tors such as in feedback networks.

Applications

Cellular Handsets

Smart Phones, PDAs

Digital Cameras

MP3 Players

Wireless LAN

Features

♦ Two 500mA Step-Down Converters

Up to 4MHz Switching Frequency

Adjustable Output from 0.6V to 3.3V

♦ Four Low-Noise LDOs with Pin-Programmable

Output Voltages

♦ One Open-Drain Driver

♦ 60ms (typ) Reset Timer

♦ Power-On/Off Control Logic and Sequencing

♦ 4mm x 4mm x 0.8mm 24-Pin Thin QFN

Dual Step-Down DC-DC Power-Management ICs

for Portable Devices

________________________________________________________________ Maxim Integrated Products

1

PART

TEMP RANGE

PIN-PACKAGE

MAX8621YETG

-40°C to +85°C

24 Thin QFN

4mm x 4mm (T2444-4)

MAX8621YETG+

-40°C to +85°C

24 Thin QFN

4mm x 4mm (T2444-4)

MAX8621ZETG

-40°C to +85°C

24 Thin QFN

4mm x 4mm (T2444-4)

MAX8621ZETG+

-40°C to +85°C

24 Thin QFN

4mm x 4mm (T2444-4)

Ordering Information

MAX8621Y

MAX8621Z

IN1

IN2

IN3

PWRON

EN3

EN4

SEL2

ENDR

REFBP

GND

OUT1

OUT2

OUT3

OUT4

DR

LX1

FB1

PGND1

LX2

FB2

PGND2

RESET

SEL1

EN2

INPUT

2.6V TO 5.5V

INPUT

OUT4

3V, 150mA

OUT3

1.8V, 150mA

OUT2

2.6V, 300mA

OUT1

2.6V, 300mA

BUCK1

1.375V, 500mA

BUCK2

1.8V, 500mA

RESET

Typical Operating Circuit

19-3539; Rev 1; 8/05

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Pin Configuration appears at end of data sheet.

EVALUATION

KIT

AVAILABLE

+ Denotes lead-free package.