EVALUATION

KIT

AVAILABLE

General Description

The MAX8645X/MAX8645Y charge pumps drive up to

eight white LEDs with regulated constant current for uni-

form intensity. The main group of LEDs (M1–M6) can be

driven up to 30mA per LED for backlighting. The flash

group of LEDs (F1 and F2) is independently controlled

and can be driven up to 200mA per LED (or 400mA total).

Two 200mA LDOs are on-board to provide power for

camera functions. The LDOs’ output voltages are pin pro-

grammable to meet different camera-module require-

ments. The MAX8645X and MAX8645Y differ only in LDO

output voltages. By utilizing adaptive 1x/1.5x/2x charge-

pump modes and very-low-dropout current regulators,

the MAX8645X/MAX8645Y achieve high efficiency over

the full 1-cell lithium-battery voltage range. The 1MHz

fixed-frequency switching allows for tiny external compo-

nents, and the regulation scheme is optimized to ensure

low EMI and low input ripple.

The MAX8645X/MAX8645Y are available in a 28-pin TQFN,

4mm x 4mm (0.8mm max height) lead-free package.

Applications

Camera Phones and Smartphones

Backlighting and Flash

PDAs, Digital Cameras, and Camcorders

Features

♦ Power Up to Eight LEDs

Up to 30mA/LED Drive for Backlight

Up to 400mA Total Drive for Flash

♦ Two Internal Low-Noise 200mA LDOs

Battery Discharge

♦ 0.2% Typical LED Current Matching

♦ Adaptive 1x/1.5x/2x Mode Switchover

♦ Flexible Brightness Control

Single-Wire, Serial-Pulse Interface (32 Steps)

2-Bit Logic (Three Levels)

♦ Low Input Ripple and EMI

♦ 2.7V to 5.5V Supply Voltage Range

♦ Soft-Start, Overvoltage, and Thermal-Shutdown

Protection

♦ 28-Pin TQFN, 4mm x 4mm Package

1x/1.5x/2x White LED Charge Pumps with

Two LDOs in 4mm x 4mm TQFN

________________________________________________________________ Maxim Integrated Products

1

Ordering Information

19-3978; Rev 3; 12/06

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.

PART

TEMP RANGE

PIN-

PACKAGE

PKG

CODE

MAX8645XETI+

-40°C to +85°C

28 TQFN-EP

4mm x 4mm

T2844-1

MAX8645YETI+

-40°C to +85°C

28 TQFN-EP

4mm x 4mm

T2844-1

Pin Configuration appears at end of data sheet.

MAIN ON/OFF

AND DIMMING

MAX8645X

MAX8645Y

1

μF

10

μF

0.01

μF

10

μF

PIN

IN

PGND

GND

P1

P2

OUT

MAIN

FLASH

OUTPUT

UP TO 580mA

1

μF

1

μF

LDO1

LDO2

C2P

C2N

1

μF

C1P

C1N

REF

SETM

SETF

CAMERA

MODULE

DUAL-LDO

VOLTAGE

SELECTION

INPUT

2.7V TO 5.5V

ENM2

ENM1

ENF

ENLDO

M1

M2

M3

M4

M5

M6

F1

F2

FLASH ON/OFF

DUAL-LDO ON/OFF

Typical Operating Circuit

EP = Exposed paddle.

+Denotes a lead-free package.