1 Features

1? Drives Up to 8 LEDs Each With Up to 25 mA of

Diode Current

? External PWM Input for Dynamic Backlight Control

? Multi-Zone Ambient Light Sensing (ALS)

? ALS Interrupt Reporting

? Independent On/Off Control for All Current Sinks

? 128 Exponential Dimming Steps With 600:1

Dimming Ratio for Group A (Up to 6 LEDs)

? 8 Linear Dimming States for Groups B (Up to 3

LEDs) and D1C (1 LED)

? Programmable Auto-Dimming Function

? Up to 90% Efficiency

? 0.55% Accurate Current Matching

? Wide Input Voltage Range (2.7 V to 5.5 V)

? Active High Hardware Enable

? Total Solution Size < 16 mm2

? Low Profile 20-Pin DSBGA Package

2 Applications

? Smart-Phone LED Backlighting

? Large Format LCD Backlighting

? General LED Lighting

3 Description

The LM3535 device is a highly integrated LED driver

capable of driving 8 LEDs in parallel for large display

applications. Independent LED control allows

selection of a subset of the 6 main display LEDs for

partial-illumination applications. In addition to the

main bank of 6, the LM3535 is capable of driving an

additional 2 independently controlled LEDs to support

Indicator applications.

The LED driver current sinks are split into three

independently controlled groups. The primary group

can be configured to drive up to six LEDs for use in

the main phone display. Groups B and C are

provided for driving secondary displays, keypads and

indicator LEDs. All of the LED current sources can be

independently turned on and off providing flexibility to

address different application requirements.

The LM3535 provides multi-zone ambient light

sensing allowing autonomous backlight intensity

control in the event of changing ambient light

conditions. A PWM input is also provided to give the

user the means to adjust the backlight intensity

dynamically based upon the content of the display.

The LM3535 provides excellent efficiency without the

use of an inductor by operating the charge pump in a

gain of 3/2 or in pass mode. The proper gain for

maintaining current regulation is chosen, based on

LED forward voltage, so that efficiency is maximized

over the input voltage range.

The LM3535 is available in a tiny 20-pin, 0.4-mm

pitch, thin DSBGA package.