LM2791 Datasheet | National Semiconductor

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 36m A of load current to acmodate two high forward voltage (typically white) LEDs. The switching frequency is 450k Hz (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 36m A output current Soft start limits inrush current Analog brightness control Separate shutdown input Very small solution size - no inductor 0.7m A typical operating current 1µA (max.) shutdown current 450k Hz 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 © 2002 National Semiconductor Corporation DS200183 .national. Connection Diagram 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...