Part # LM27951 datasheet

Part Manufacturer: National Semiconductor

National Semiconductor

Part Description: LM27951 White LED Adaptive 1.5X 1X Switched Capacitor Current Driver


Part Details:

LM27951 November 2005 LM27951 White White LED Adaptive 1.5X/1X Switched Capacitor CurrentDriver LED General Description Features The LM27951 is a switched capacitor white-LED driver ca- n Drives up to 4 LEDs with up to 30mA each Adaptive pable of driving up to 4 LEDs with 30mA through each LED. n Regulated current sources with 0.2%(typ.) matching Its 4 tightly regulated current sources ensure excellent LED n 3/2x, 1x Gain transition based on LED VF current and brightness matching. LED drive current is pro- n Peak Efficiency Over 85% grammed by an external sense resistor. The LM27951 oper- n Input Voltage Range: 2.8V to 5.5V ates over an input voltage range from 2.8V to 5.5V and n PWM Brightness Control requires only four low-cost ceramic capacitors. n Very Small Solution Size - NO INDUCTOR 1.5X/1X The LM27951 provides excellent efficiency without the use n Fixed 750kHz Switching Frequency 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 n <1µA Shutdown Current input voltage range by actively selecting the proper gain n 14-pin LLP Package: 4.0mm X 3.0mm X 0.8mm based on the LED forward voltage requirements. The LM27951 uses constant frequency pre-regulation to Applications Switched minimize conducted noise on the input. It has a fixed 750kHz n White LED Display Backlights switching frequency optimized for portable applications. The n White LED Keypad Backlights LM27951 consumes less than 1µA of supply current when n General Purpose LED Lighting shut down. The LM27951 is available in a 14-pin No-Pullback LeadlessLeadframe Package: LLP-14. Capacitor Typical Application Circuit Current Driver 20171701 © 2006 National Semiconductor Corporation DS201717 www.national.com Connection Diagram LM27951 LM27951 14-pin No-Pullback Leadless Leadframe Package (LLP-14)


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LM27951.pdf Datasheet