MAX1820 Просмотр технического описания (PDF) - Maxim Integrated

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MAX1820

WCDMA Cellular Phone 600mA Buck Regulators

Maxim Integrated 

19-2011; Rev 3; 4/05

EVAALVUAAILTAIOBNLEKIT

WCDMA Cellular Phone 600mA

Buck Regulators

General Description

The MAX1820/MAX1821 low-dropout, pulse-width-mod-

ulated (PWM) DC-DC buck regulators are optimized to

provide power to the power amplifier (PA) in WCDMA

cell phones; however, they may be applied in many

other applications where high efficiency is a priority. The

supply voltage range is from 2.6V to 5.5V, and the guar-

anteed output current is 600mA; 1MHz PWM switching

allows for small external components, while skip mode

reduces quiescent current to 180µA with light loads.

The MAX1820 is dynamically controlled to provide vary-

ing output voltages from 0.4V to 3.4V. The circuit is

designed such that the output voltage settles in <30µs

for a full-scale change in voltage and current. The

MAX1821 is set with external resistors to provide any

fixed output voltage in the 1.25V to 5.5V range.

The MAX1820/MAX1821 include a low on-resistance

internal MOSFET switch and synchronous rectifier to

maximize efficiency and minimize external component

count; 100% duty-cycle operation allows for low dropout

of only 150mV at 600mA load, including the external

inductor resistance. The devices are offered in 10-pin

µMAX® and tiny 3 ✕ 4 chip-scale (UCSP™) packages.

________________________Applications

WCDMA Cell Phone Power Amplifiers

PDA, Palmtop, and Notebook Computers

Microprocessor Core Supplies

Digital Cameras

PCMCIA and Network Cards

Hand-Held Instruments

Typical Operating Circuits continued at end of data sheet.

Ordering Information continued at end of data sheet.

Pin Configurations appear at end of data sheet.

UCSP is a trademark of Maxim Integrated Products, Inc.

µMAX is a registered trademark of Maxim Integrated Products, Inc.

Features

♦ Dynamically Adjustable Output from 0.4V to 3.4V

(MAX1820)

♦ Programmable Output from 1.25V to 5.5V

(MAX1821)

♦ SYNC to 13MHz External Clock (MAX1820X)

♦ SYNC to 19.8MHz External Clock (MAX1820Y)

♦ NO SYNC, Internal 1MHz Oscillator (MAX1820Z)

♦ Low Quiescent Current

180µA (typ) in Skip Mode

0.1µA (typ) in Shutdown Mode

♦ No External Schottky Diode Required

♦ 600mA Guaranteed Output Current

♦ 0% to 100% Duty-Cycle Operation

♦ 150mV Dropout at 600mA Load (Including RDC

of External Inductor)

♦ µMAX or UCSP Packaging

Typical Operating Circuits

INPUT

2.6V TO

5.5V

13MHz

OR

19.8MHz

VOUT CONTROL

DAC

BATT

SHDN

LX

OUT

PGND

MAX1820

SYNC COMP

4.7µH

REF

SKIP GND

DYNAMIC

OUTPUT

0.4V TO 3.4V

4.7µF

Ordering Information

PART

SYNC

OUTPUT VOLTAGE

FREQ (MHz)

TEMP RANGE

PIN-PACKAGE

UCSP MARK

MAX1820ZEBC*

No Sync

Dynamic

-40°C to +85°C

3 ✕ 4 UCSP

AAB

MAX1820YEBC*

19.8

Dynamic

-40°C to +85°C

3 ✕ 4 UCSP

AAL

MAX1820XEBC*

13

Dynamic

-40°C to +85°C

3 ✕ 4 UCSP

AAM

MAX1820ZEUB

No Sync

Dynamic

-40°C to +85°C

10 µMAX

—

MAX1820YEUB

19.8

Dynamic

-40°C to +85°C

10 µMAX

—

MAX1820XEUB

13

Dynamic

-40°C to +85°C

10 µMAX

—

*UCSP reliability is integrally linked to the user’s assembly methods, circuit board material, and environment. See the UCSP Reliability

Notice in the UCSP Reliability section of this data sheet for more information.

________________________________________________________________ Maxim Integrated Products 1

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.

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