LED1

VOUT

GND

ISET

LED2

LED3

LED4

VIN

C2+

C2-

EN1

EN2

C1+

C1-

CTRL

Single-Wire On/Off and

Dimming Control

A8435

2.7 to 5.5 V

RSET

C2

CIN

1 µF

COUT

1 µF

1 µF

1 µF

C1

A8435

LED1

VOUT

GND

ISET

LED2

LED3

LED4

VIN

C2+

C2–

EN1

EN

NC

2

C1+

C1–

CTRL

On/Off and

Dimming Control

2.7 to 5.5 V

RSET

C2

CIN

1 µF

COUT

1 µF

1 µF

1 µF

C1

Figure 1. Typical Circuit. Dual wire control configuration: 2-bit

parallel or PWM dimming.

Figure 2. Typical Circuit. Single wire control configuration.

A8435-DS, Rev. 1

Description

The A8435 high efficiency charge pump IC offers a simple,

low-cost white LED driver solution for portable electronics

display applications. Using a proprietary control scheme (1×,

1.5×), the A8435 can output well-matched currents for up to

4 LEDs, while maintaining the highest efficiency over most

of the Li-ion battery lifetime.

The A8435 accepts an input range of 2.7 to 5.5 V and delivers

up to 30 mA for each of the four regulated current sources. The

A8435 can deliver a total continuous output current of 120 mA,

meeting the requirements of most Li-ion battery-powered white

LED backlight applications. Outputs can also be tied together

for WLED flash/torch applications.

The A8435 offers flexible options for LED current driving.

The LED current can be set by any of the following methods:

(a) choosing an appropriate value for RSET, (b) 2-bit

parallel control with 3 levels, (c) PWM control, or (d) serial

programming

TheA8435 is available in a very thin profile 0.75 mm (nominal

height) 3 × 3 mm QFN/MLP-16 package (ES), fitting the needs

of space-conscious applications.

Features and Benefits

▪ Proprietary adaptive control scheme (1×, 1.5×)

▪ Maximum efficiency, over 92%

▪ 0.5% LED current matching

▪ 1 MHz operating frequency

▪ Flexible dimming control:

▫ Serial 11-level dimming, down to 5%

▫ PWM

▫ 2-bit parallel

▪ Drives up to 4 white LEDs

▪ 30 mA per LED

▪ 120 mA total continuous output

▪ Low input ripple and EMI

▪ Soft-start limits inrush current

▪ Short circuit protection

▪ Overvoltage protection

▪ Thermal shutdown protection

▪ Space-saving MLP-16 package: 3 × 3 mm footprint

▪ Very thin 0.75 mm nominal height package

High Efficiency Charge Pump White LED Driver

Package: 16 pin QFN/MLP (suffix ES)

Typical Applications

A8435

Approximate Scale

▪ White LED backlights for cellular phones, PDAs

▪ Digital cameras, camcorders

▪ Portable audio devices

▪ Other portable device white LED backlighting

▪ 120 mA WLED flash/torch

Applications include: