_______________________________________________________________ Maxim Integrated Products 1

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.

High-Efficiency PWM LED Driver with Boost

Converter and Five Constant-Current GPIO Ports

General Description

The MAX6948B general-purpose input/output (GPIO)

peripheral drives a series string of white LEDs (WLEDs),

and contains up to five general-purpose input/output

(GPIO) ports to drive additional LEDs.

The integrated 2MHz boost converter minimizes the size

and cost of external components and supplies 30mA of

load current at up to 28V. The converter is stable under

all load conditions from 5V up to 28V and includes

open-circuit detection to prevent damage to the IC. An

signal enables 1024 levels of WLED intensity.

The five GPIO ports function as logic inputs, open-

drain logic outputs, or constant-current sinks in any

combination. Ports withstand 5.5V independent of the

MAX6948B’s supply voltage. Two of the ports drive addi-

tional LEDs up to 30mA/port, while the other three ports

drive LEDs at up to 10mA/port. The MAX6948B features

shutdown and standby modes for low-power dissipa-

tion. The constant-current drivers contain programmable

PWM outputs and allow staggering to reduce the input

peak-current requirements. The I/O ports also feature

ramp-up and ramp-down controls.

The MAX6948B features a single input to select from four

the five GPIO ports is identical to the MAX6946/MAX6947

I/O expanders.

The MAX6948B is available in a 25-bump (2.31mm x

2.31mm) WLP package for cell phones, PDAs, and

other portable consumer electronic applications. The

MAX6948B operates over the -40NC to +105NC tempera-

ture range.

Applications

LED Backlighting for LCDs

Cell Phones

PDAs

Handheld Games

Portable Consumer Electronics

Features

S

28V Step-Up DC-DC Converter with Integrated

nMOS Power Switch

S

Built-In 10-Bit PWM Control for Improved Efficiency

S

No Discharge Path During PWM Off Period for

Increased Battery Life

S

Fixed 2MHz Switching for Smaller Components

Drives up to 6 Series WLEDs

S

±8kV Human Body Model (HBM) ESD Protection

for GPIOs and Boost-Converter Output

S

Five Open-Drain GPIOs Capable of Constant-

Current LED Drive with Individual 8-Bit PWM

Intensity Control

S

2.7V to 5V Power-Supply Operation

S

S

S

RST Input Clears Serial Interface and Exits

Shutdown (Reset-Run Option)

S

Small (2.31mm x 2.31mm) WLP Package

19-4935; Rev 0; 9/09

Ordering Information

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

Typical Operating Circuit

EVALUATION

KIT

AVAILABLE

2.7V TO 5.0V

1.7V TO V+

LX

V+

SCL

SDA

RST

SCL

SDA

RST

COMP

AD0

GND

OUT

PGND

FB

LEDSW

B

G

R

P0

P1

P2

P3

P4

0.22FF

10

µH

0.1FF

47nF

MAX6948B

2.2FF

PART

TEMP RANGE

PIN-PACKAGE

MAX6948BGWA+

-40NC to +105NC

25 WLP