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Details, datasheet, quote on part number:LM2791LD-L
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| Part: | LM2791LD-L |
| Category: | Optoelectronics => Drivers/Controllers => LEDs => White-LED Drivers |
| Description: | LM2791 - Current Regulated Switched Capacitor Led Driver With Analog Brightness Control, Package: Evaluation Board, Pin Nb=- |
| Company: | National Semiconductor Corporation |
| Datasheet: | Download LM2791LD-L datasheet File size : 232 kB |
| Request For quote: | Find where to buy LM2791LD-L
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Datasheet text preview:
LM2791 Current Regulated Switched Capacitor LED Driver with Analog Brightness Control
July 2002
LM2791 Current Regulated Switched Capacitor LED Driver with Analog Brightness Control
General Description
The LM2791 is a CMOS charge-pump voltage doubler and regulator that provides two regulated current sources. The LM2791 is designed to drive two white (or blue) LEDs with matched currents (within ± 0.3%) to produce balanced light sources for display backlights. They accept an input voltage range from 3V to 5.8V and maintain a constant current determined by an external set resistor. The LM2791 delivers up to 36mA of load current to accommodate two high forward voltage (typically white) LEDs. The switching frequency is 450kHz (min.) to keep the conducted noise spectrum away from sensitive frequencies within portable RF devices. In the LM2791, brightness is controlled by applying a voltage between GND and 3.0V to the BRGT pin. The LM2791 is available in active high or low shutdown versions. The shutdown pin reduces the operating current to 1µA (max.). The LM2791 is available in a 10 pin leadless leadframe (LLP) CSP package.
Features
n n n n n n n n n n n n n Output matching of ± 0.3% Drives up to two LED's 3V to 5.8V Input Voltage Up to 36mA output current Soft start limits inrush current Analog brightness control Separate shutdown input Very small solution size - no inductor 0.7mA typical operating current 1µA (max.) shutdown current 450kHz switching frequency (min.) Linear regulation generates predictable noise spectrum LLP-10 package: 3mm X 3mm X 0.8mm
Applications
n White LED Display Backlights n White LED Keypad Backlights n 1-Cell Li-Ion battery-operated equipment including PDAs, hand-held PCs, cellular phones n Flat Panel Dispalys
Basic Application Circuit
20018301
© 2002 National Semiconductor Corporation
DS200183
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LM2791
Connection Diagram
20018303
Top View 10-Lead LLP
Ordering Information
Order Number LM2791LD-L LM2791LDX-L LM2791LD-H LM2791LDX-H Shutdown Polarity Active Low Active Low Active High Active High NSC Package Drawing LLP-10 LLP-10 LLP-10 LLP-10 Package Marking SNB SNB SLB SLB Supplied As 1000 Units, Tape and Reel 4500 Units, Tape and Reel 1000 Units, Tape and Reel 4500 Units, Tape and Reel
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LM2791
Pin Description
Pin 1 2 3 4 5 6 7 8 9 10 Name BRGT POUT C1- C1+ D2 D1 GND VIN SD/SD ISET Charge pump output. Connect this pin to the negative terminal of C1. Connect this pin to the positive terminal of C1. Current source outputs. Connect directly to LED. Current source outputs. Connect directly to LED. Power supply ground input. Power supply voltage input. Shutdown input. Device operation is inhibited when pin is asserted. Current Sense Input. Connect resistor to ground to set constant current through LED. Function Variable voltage input controls output current.
Block Diagram
20018302
3
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