RoHS Compliance Information	Size in Kbytes	Date
LM2755 Charge Pump LED Controller with I2C Compatible Interface in Micro SMD	1670 Kbytes	26-Oct-07	View Online Download

Part Number

Package

Factory Lead Time

Models

Samples & Electronic Orders

Budgetary Pricing

Std Pack Size

Package Marking Format

Type

Pins

Spec.

MSL Rating

Peak Reflow

RoHS Report

CAD Symbols

Weeks

Qty

Qty

$US each

LM2755TMEV

LM2755TM Evaluation Board

Full production

N/A

1+

$115.00

1

-

6 weeks

N/A

LM2755TM

MICRO SMD

18

NOPB

1

260

RoHS

N/A

Full production

N/A

1K+

$1.50

reel of 250

XYTT I D32

6 weeks

N/A

LM2755TMX

MICRO SMD

18

NOPB

1

260

RoHS

N/A

Full production

N/A

1K+

$1.50

reel of 3000

XYTT I D32

6 weeks

N/A

General Description

The LM2755 is a charge-pump-based, constant current LED driver capable of driving 3 LEDs with a total output current up to 90mA. The diode current waveforms of each LED can be trapezoidal with timing and level parameters (rise time, fall time, high level, low level, delay, high time, low time) programmed via an I 2C compatible interface. The 32 brightness levels found on the LM2755 are exponentially spaced (as opposed to linearly spaced) to better match the response of the human eye to changing brightness levels.

The device requires only four small and low-cost ceramic capacitors. The LM2755 provides excellent efficiency without the use of an inductor by operating the charge pump in a gain of 3/2 or in a gain of 1. Maximum efficiency is achieved over the input voltage range by actively selecting the proper gain based on the LED forward voltage requirements.

The pre-regulation scheme used by the LM2755 is optimized to ensure low conducted noise on the input. An internal soft-start circuitry eliminates high inrush current at start-up. The LM2755 consumes 3µA (typ.) of supply current in shut-down.

The LM2755 is available in National’s tiny 18-bump thin micro SMD package.

Application Notes

Title	Size in Kbytes	Date
AN-1778: Application Note 1778 LM2755 Charge Pump LED Controller with I2C Compatible Interface in µSMD	4110 Kbytes	30-Apr-08	Download
AN-1777: Application Note 1777 Designing Energy-Efficient Handheld Illumination Solutions	156 Kbytes	27-Feb-08	Download

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