Rainbow Electronics MAX8649 User Manual

General description, Applications, Features

General Description

The MAX8649 high-efficiency DC-to-DC step-down
switching regulator delivers up to 1.8A of output current.
The device operates from a 2.5V to 5.5V input voltage
range, making it future proof for next-generation battery
technologies. The output voltage is I

C programmable

from 0.75V to 1.38V. Fully differential remote sense
ensures precise DC regulation at the load. Total output
error is less than 2% over load, line, and temperature.

The MAX8649 operates at a 3.25MHz fixed frequency.
The high operating frequency minimizes the size of exter-
nal components. The switching frequency of the converter
can be synchronized to the master clock of the applica-
tion. When synchronizing to an external clock, the
MAX8649 measures 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-
grammed directly through the I

C interface, or by

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.

Applications

Cell Phones and Smartphones

PDAs and MP3 Players

Features

♦ 1.8A Guaranteed Output Current
♦ I

C Programmable V

OUT

(750mV to 1.38V in 10mV

Steps)

♦ Operates from 2.5V to 5.5V Input Supply
♦ On-Chip FET and Synchronous Rectifier
♦ Fixed 3.25MHz PWM Switching Frequency
♦ Synchronizes to 13MHz, 19.2MHz, or 26MHz

System Clock when Available

♦ Small 1.0µH Inductor
♦ Initial Accuracy 0.5% at 1.25V Output
♦ 2% Output Accuracy Over Load, Line, and

Temperature

♦ Power-Save Mode Increases Light Load Efficiency
♦ Overvoltage and Overcurrent Protection
♦ Thermal Shutdown Protection
♦ 400kHz I

C Interface

♦ < 1µA Shutdown Current
♦ 16-Bump, 2mm x 2mm WLP Package

MAX8649

1.8A Step-Down Regulator with Differential

Remote Sense in 2mm x 2mm WLP

________________________________________________________________

Maxim Integrated Products

19-4504; Rev 0; 9/09

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.

Ordering Information

PART

TEMP RANGE

PIN-PACKAGE

MAX8649EWE+T

-40°C to +85°C

16 Bump WLP

(0.5mm pitch)

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

Pin Configuration

WLP 0.5mm PITCH

IN1

AGND

IN2

SNS-

VID0

PGND

SDA

SCL

SYNC

VID1

SNS+

TOP VIEW

(BUMPS ON BOTTOM

Typical Operating Circuit

2.5V TO

5.5V

OUT

(0.75V TO
1.38V)

IN2

SCL

0V TO

4.0V