LM2791  Product Folder

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.

• 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

• White LED Display Backlights
• White LED Keypad Backlights
• 1-Cell Li-Ion battery-operated equipment including PDAs, hand-held PCs, cellular phones
• Flat Panel Dispalys