70%

72%

74%

76%

78%

80%

82%

84%

86%

88%

90%

92%

2.5

3

3.5

4

4.5

5

5.5

VIN (V)

Three String, L=22µH, 1MHz

3s3p

4s3p

5s3p

6s3p

7s3p

C049

IN

SW

HVLED1

PGND

HWEN

SDA

SCL

COUT

CIN

L

D1

PWM

OVP

VIN = 2.7V to 5.5V

VOUT up to 40V

VIN

HVLED3

HVLED2

Product

Folder

Order

Now

Technical

Documents

Tools &

Software

Support &

Community

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.

LM3697

SNOSCS2D – NOVEMBER 2013 – REVISED MARCH 2019

LM3697 High-efficiency three-string white LED driver

1

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

high-

performance 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 high-

voltage current sink.

The

LM3697

is

fully

configurable

via

an

I2C-

compatible 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.

Device Information(1)

ORDER NUMBER

PACKAGE

BODY SIZE (MAX)

LM3697

DSBGA (12)

1.64 mm × 1.29 mm

(1) For all available packages, see the orderable addendum at

the end of the data sheet.

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Simplified Schematic

Boost Efficiency