General Description

The MAX8649/MAX8649A high-efficiency DC-to-DC step-

down switching regulators deliver up to 1.8A of output cur-

rent. The device operates from a 2.5V to 5.5V input

voltage range, making it future proof for next-generation

mable from 0.75V to 1.38V. Remote sense ensures pre-

cise DC regulation at the load. Total output error is less

than 2% over load, line, and temperature.

The ICs operate at a 3.25MHz fixed frequency. The high

operating frequency minimizes the size of external com-

ponents. The switching frequency of the converter can be

synchronized to the master clock of the application. When

synchronizing to an external clock, the ICs measure the

frequency of the external clock to ensure that the clock is

stable before changing the switching frequency to the

external clock frequency.

An on-board DAC allows adjustment of the output volt-

age in 10mV steps. The output voltage can be pro-

preloading a set of on-board registers and using the

two VID logic signals to select the appropriate register.

Other features include internal soft-start control circuitry

to reduce inrush current, output overvoltage, overcur-

rent, and overtemperature protection.

may be used in a system. For a 2.5A version of this

device, refer to the MAX8952 data sheet.

Applications

Cell Phones and Smartphones

PDAs and MP3 Players

Features

o 1.8A Guaranteed Output Current

Steps)

o Operates from 2.5V to 5.5V Input Supply

o On-Chip FET and Synchronous Rectifier

o Fixed 3.25MHz PWM Switching Frequency

o Synchronizes to 13MHz, 19.2MHz, or 26MHz

System Clock when Available

o Small 1.0µH Inductor

o Initial Accuracy 0.5% at 1.25V Output

o 2% Output Accuracy Over Load, Line, and

Temperature

o Power-Save Mode Increases Light Load Efficiency

o Overvoltage and Overcurrent Protection

o Thermal Shutdown Protection

o < 1µA Shutdown Current

o 16-Bump, 2mm x 2mm WLP Package

1.8A Step-Down Regulator with

Remote Sense in 2mm x 2mm WLP

________________________________________________________________

Maxim Integrated Products

1

19-4504; Rev 4; 6/11

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.

EVALUATION

KIT

AVAILABLE

Ordering Information

PART

PIN-PACKAGE

(WRITE/READ)

MAX8649EWE+T

16 WLP (0.5mm pitch)

0xC0/0xC1

MAX8649AEWE+T 16 WLP (0.5mm pitch)

0xC4/0xC5

+

Denotes a lead(Pb)-free/RoHS-compliant package.

Note: All devices operate over the -40°C to +85°C temperature

range.

Bump Configuration

+

WLP 0.5mm PITCH

B2

B4

C4

B3

B1

A4

A3

A2

A1

D4

C1

D1

C3

C2

D3

D2

IN1

AGND

IN2

EN

LX

LX

SNS-

VID0

PGND

PGND

SDA

SCL

SYNC

VID1

SNS+

TOP VIEW

(BUMPS ON BOTTOM)

Typical Operating Circuit

2.5V TO

5.5V

(0.75V TO

1.38V)

LX

IN2

SCL

1.8V TO

3.6V

2.5V TO

5.5V

11

Ω

0.1

μF

10

μF

0.1

μF

10

μF

0.1

μF

SDA

IN1

FSYNC

PGND

SNS+

SNS-

EN

VID0

VID1

AGND

MAX8649

MAX8649A

1

μH

CPU

0.1

μF

2.2

μF