1 Features

1• Drives three parallel high-voltage led strings for

display and keypad lighting

• High-voltage strings capable of up to 40-V output

voltage and up to 90% efficiency

• Up to 30 mA per current sink

• 11-Bit configurable dimming resolution

• PWM input for content adjustable brightness

control (CABC)

• Fully configurable LED grouping and control

• Integrated 1-A/40-V MOSFET

• Adaptive boost output to LED voltages

• Selectable 500-kHz and 1-MHz switching

frequency

• Four configurable overvoltage protection

thresholds (16 V, 24 V, 32 V, and 40 V)

• Overcurrent protection

• Thermal shutdown protection

• 29-mm2 Total solution size

2 Applications

• Power source for smart phone illumination

• Display, keypad, and indicator illumination

3 Description

The LM3697 11-bit LED driver provides highperformance

backlight dimming for 1, 2, or 3 series

LED strings while delivering up to 90% efficiency. The

boost converter with integrated 1-A, 40-V MOSFET

automatically adjusts to LED forward voltage to

minimize headroom voltage and effectively improve

LED efficiency.

The LM3697 is a high-efficiency three-string power

source for backlight or keypad LEDs in smart-phone

handsets. The high-voltage inductive boost converter

provides the power for three-series LED strings for

display backlight and keypad functions (HVLED1,

HVLED2, and HVLED3).

An additional feature is a pulse width modulation

(PWM) control input for content adjustable backlight

control, which can be used to control any highvoltage

current sink.

The LM3697 is fully configurable via an I2Ccompatible

interface. The device operates over a

2.7-V to 5.5-V input voltage range and a −40°C to

+85°C temperature range.