General Description

The MAX8805W/MAX8805X/MAX8805Y/MAX8805Z

high-frequency step-down converters are optimized for

dynamically powering the power amplifier (PA) in

WCDMA or NCDMA handsets. The devices integrate a

high-efficiency PWM step-down converter for medium-

and low-power transmission, and a 60mΩ typical

bypass FET to power the PA directly from the battery

during high-power transmission. Dual 200mA low-noise,

high-PSRR low-dropout regulators (LDOs) for PA bias-

ing are also integrated.

Two switching frequency options are available (2MHz for

the MAX8805W/MAX8805Y and 4MHz for the MAX8805X/

MAX8805Z), allowing optimization for smallest solution

size or highest efficiency. Fast switching allows the use of

small ceramic 2.2µF input and output capacitors while

maintaining low ripple voltage. The feedback network is

integrated, further reducing external component count

and total solution size.

The MAX8805W/MAX8805X/MAX8805Y/MAX8805Z use

an analog input driven by an external DAC to control

the output voltage linearly for continuous PA power

adjustment. The REFIN to OUT gain is available in two

options (2V/V for the MAX8805Y/MAX8805Z and 2.5V/V

for the MAX8805W/MAX8805X). At high-duty cycle, the

MAX8805W/MAX8805X/MAX8805Y/MAX8805Z auto-

matically switch to the bypass mode, connecting the

input to the output through a low-impedance (60mΩ

typ) MOSFET. The user can also enable the bypass

mode directly through a logic-control input.

The LDOs in the MAX8805W/MAX8805X/MAX8805Y/

MAX8805Z are designed for low-noise operation

through its own logic control interface.

The MAX8805W/MAX8805X/MAX8805Y/MAX8805Z are

available in a 16-bump, 2mm x 2mm WLP package

(0.7mm max height).

Features

♦ PA Step-Down Converter

7.5µs (typ) Settling Time for 0.8V to 3.4V Output

Voltage Change

Dynamic Output Voltage Setting from 0.4V to

60mΩ pFET and 100% Duty Cycle for Low

Dropout

2MHz or 4MHz Switching Frequency

Low Output-Voltage Ripple

600mA (MAX8805Y/MAX8805Z) or 650mA

(MAX8805W/MAX8805X) Output Drive

Capability

2% Maximum Accuracy

Tiny External Components

♦ Dual Low-Noise LDOs

High 70dB (typ) PSRR

Guaranteed 200mA Output Drive Capability

Individual ON/OFF Control

♦ Low 0.1µA Shutdown Current

♦ 2.7V to 5.5V Supply Voltage Range

♦ Thermal Shutdown

♦ Tiny 2mm x 2mm x 0.7mm WLP Package

(4 x 4 Grid)

600mA/650mA PWM Step-Down Converters in

2mm x 2mm WLP for WCDMA PA Power

________________________________________________________________

Maxim Integrated Products

1

Ordering Information

19-0777; Rev 1; 10/07

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

+

Denotes a lead-free package.

T = Tape and reel package.

*

xy is the output voltage code (see Table 1).

Note: All devices are specified over the -40°C to +85°C operating temperature range.

Pin Configuration appears at end of data sheet.

PART

PIN-

PACKAGE

PKG

CODE

SWITCHING

FREQUENCY

REFIN TO OUT GAIN

MAX8805WEWExy+T*

16 WLP-16

W162B2+1

2MHz

2.5V/V

MAX8805XEWExy+T*

16 WLP-16

W162B2+1

4MHz

2.5V/V

MAX8805YEWExy+T*

16 WLP-16

W162B2+1

2MHz

2V/V

MAX8805ZEWExy+T*

16 WLP-16

W162B2+1

4MHz

2V/V

Applications

WCDMA/NCDMA Cellular Handsets

Wireless PDAs

Smartphones