LM2756 Datasheet, PDF (1/25 Pages) National Semiconductor (TI) – Multi-Display Inductorless LED Driver with 32 Exponential Dimming Steps in μSMD

LM2756
www.ti.com
SNVS504B – JULY 2007 – REVISED DECEMBER 2007
LM2756 Multi-Display Inductorless LED Driver with 32 Exponential Dimming Steps in
micro SMD
Check for Samples: LM2756
FEATURES
1
•2 Drives up to 8 LEDs with up to 30mA of Diode
Current Each
• 32 Exponential Dimming Steps with 800:1
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
• 3 Independently Controlled LED Groups Via
I²C Compatible Interface
• Up to 90% Efficiency
• Total Solution Size < 21mm²
• Low Profile 20 Bump micro SMD Package
(1.615mm × 2.015mm × 0.6mm)
• 0.4% Accurate Current Matching
• Internal Soft-Start Limits Inrush Current
• True Shutdown Isolation for LED’s
• Wide Input Voltage Range (2.7V to 5.5V)
• Active High Hardware Enable
APPLICATIONS
• Dual Display LCD Backlighting for Portable
Applications
• Large Format LCD Backlighting
• Display Backlighting with Indicator Light
DESCRIPTION
The LM2756 is a highly integrated, switched-capacitor, multi-display LED driver that can drive up to 8 LEDs in
parallel with a total output current of 180mA. Regulated internal current sources deliver excellent current and
brightness matching in all LEDs.
The LED driver current sinks are split into three independently controlled groups. The primary group (Group A)
can be configured to drive four, five or six LEDs for use in the main phone display, while the secondary group
(Group B) can be configured to drive one, two or three LEDs for driving secondary displays, keypads and/or
indicator LEDs. An additional driver, D1C, is provided for additional indicator lighting functions.
The device 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 LM2756 is available in National’s tiny 20-bump, 0.4mm pitch, thin micro SMD package.
1
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2007, Texas Instruments Incorporated