MAX8822 Maxim Integrated Products, MAX8822 Datasheet

MAX8822

Manufacturer Part Number

MAX8822

Description

Ultra-Efficient Negative Charge-Pump LED Driver

Manufacturer

Maxim Integrated Products

Datasheet

1.MAX8822.pdf (15 pages)

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The MAX8822 drives up to four white light-emitting

diodes (LEDs) with regulated constant current for dis-

play backlighting in cell phones, digital cameras, PDAs,

and other handheld devices. By utilizing a proprietary

negative 0.5x inverting charge pump and innovative

independent low-dropout (LDO) adaptive current regu-

lators, very high efficiency is achieved over the full

1-cell Li+ battery voltage range, even with large LED V

mismatch. The 1MHz fixed-frequency switching allows

for tiny external components. The regulation scheme is

optimized to ensure low EMI and low input ripple. Two

200mA, low-noise, high power-supply-rejection-ratio

(PSRR) LDOs with programmable output voltages are

included on-chip to provide power to camera modules

or other devices.

The MAX8822 features a single-wire, serial-pulse control-

logic interface that programs LED current and the output

voltages of the LDOs. The LED dimming range is pseu-

do-logarithmic from 24mA to 0.1mA in 31 steps. LDO

output voltages are programmable in 16 different combi-

nations to meet various camera module requirements.

The MAX8822 includes soft-start, thermal shutdown,

open- and short-circuit protection.

19-0847; Rev 0; 11/07

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.

Driver with Dual LDOs in 3mm x 3mm Thin QFN

INTERFACE

CONTROL

SERIAL-

PULSE

White LED Backlighting

Cell Phones and Smartphones

2.7V TO 5.5V

0.1μF

4.7μF

INPUT

Ultra-Efficient Negative Charge-Pump LED

GND

ENLED

ENLDO

REF

Typical Operating Circuit

C1P

________________________________________________________________ Maxim Integrated Products

1μF

C1N

MAX8822

General Description

C2P

1μF

C2N

LED2

LED3

LED4

LDO1

LDO2

LED1

NEG

Applications

UP TO 24mA/LED

1μF

2.2μF

1μF

LDO1

LDO2

♦ High-Efficiency Charge Pump for Up to Four

♦ Dual 200mA Low-Noise, High PSRR LDOs

♦ Flexible Single-Wire Control for Dimming and

♦ Low 0.5µA (typ) Shutdown Mode

♦ Soft-Start Limits Inrush Current

♦ Thermal Shutdown and Open- and Short-Circuit

♦ Tiny 16-Pin, 3mm x 3mm Thin QFN Package

Note: The device is specified over the -40°C to +85°C extend-

ed temperature range.

+ Denotes a lead-free package.

* EP = Exposed paddle.

MAX8822ETE+

White LEDs

LDO Output Voltage

Protection

(0.8mm max Height) with Exposed Paddle

Independent Adaptive Voltage Supply for Each

24mA to 0.1mA Dimming Range

1% (typ) Current Accuracy and 0.3% Current

Low 65µA (typ) Quiescent Current

16 Different Output Voltage Combinations Up to

High 60dB PSRR at 10kHz

PART

TOP VIEW

LED

Matching

3.3V

ENLDO

ENLED

LDO2

REF

PIN-PACKAGE

16 Thin QFN-EP*

(3mm x 3mm)

Ordering Information

(3mm x 3mm)

THIN QFN

MAX8822

Pin Configuration

TOP MARK

AFW

Features

LED4

NEG

C1N

C2N

T1633-5

CODE

PKG

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