LM3554 PRODUCT BRIEF Synchronous Boost Converter with 1.2A Dual High Side LED Drivers and I2C Compatible Interface General Description Features The LM3554 is a 2 MHz fixed frequency, current mode synchronous boost converter. The device is designed to operate as a dual 600mA (1.2A total) constant current driver for high current white LEDs, or as a regulated 4.5V or 5V voltage source. The dual high side current sources allow for grounded cathode LED operation. An adaptive regulation method ensures the current source for each LED remains in regulation and maximizes efficiency. The main features include: an I2C compatible interface for controlling the LED current or the desired output voltage, a hardware Flash enable input for direct triggering of the Flash pulse, and dual TX inputs which force the Flash pulse into a low current Torch mode allowing for synchronization to RF power amplifier events or other high current conditions. Additionally, an active high hardware enable (HWEN) input provides a hardware shutdown during system software failures. Five protection features are available within the LM3554 including a software selectable input voltage monitor, an internal comparator, for interfacing with an external temperature sensor, four selectable current limits to ensure the battery current is kept below a predetermined peak level, an overvoltage protection feature to keeps the output voltage below the OVP threshold in case of an open LED, and an output short circuit protection which limits the output current during an output short to GND. Additionally, the device provides various fault indicators including: a thermal fault flag indicating the LED temperature has tripped the thermal threshold, a flag indicating a TX event has occured, a flag indicating the flash timeout counter has expired, a flag indicating the devices die temperature has reached the thermal shutdown threshold, and a flag indicating an open or short LED. Notice: This document is not a full datasheet. For more imformation regarding this product, or to order samples, please contact your National Semiconductor sales office or visit http://www.national.com/support/dir.html. ■ Dual High Side Current Sources ■ Grounded Cathode Allowing for Better Heatsinking and © 2009 National Semiconductor Corporation 300420 LED Routing ■ >90% Efficiency ■ Ultra-Small Solution Size: < 23mm2 ■ Four Operating Modes: Torch, Flash, LED Indicator and Voltage Output ■ Accurate and Programmable LED Current from 37.5mA to ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 1.2A Programmable 4.5V or 5.0V Constant Output Voltage Hardware Flash and Torch Enable LED Thermal Sensing and Current Scaleback Software Selectable Input Voltage Monitor Programmable Flash Timeout Dual Synchronization Inputs for RF Power Amplifier Pulse Events Open and Short LED Detection Active High Hardware Enable for Protection Against System Faults 400kHz I2C Compatible Interface 16-Bump (1.7mm × 1.7mm × 0.6mm) µSMD Applications ■ Camera Phone LED Flash Controller ■ Class D Audio Amplifier Power ■ LED Current Source Biasing www.national.com LM3554 PRODUCT BRIEF June 8, 2009 LM3554 Typical Application Circuits 30042001 www.national.com 2 LM3554 Physical Dimensions inches (millimeters) unless otherwise noted 16 Bump µSMD (0.4mm pitch) For Ordering, Refer to Ordering Information Table NS Package Number TMD16CCA X1 = 1.695mm (±0.03mm), X2 = 1.695mm (±0.03mm), X3 = 0.6mm(±0.075mm) 3 www.national.com LM3554 PRODUCT BRIEF Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Design Support Amplifiers www.national.com/amplifiers WEBENCH® Tools www.national.com/webench Audio www.national.com/audio App Notes www.national.com/appnotes Clock and Timing www.national.com/timing Reference Designs www.national.com/refdesigns Data Converters www.national.com/adc Samples www.national.com/samples Interface www.national.com/interface Eval Boards www.national.com/evalboards LVDS www.national.com/lvds Packaging www.national.com/packaging Power Management www.national.com/power Green Compliance www.national.com/quality/green Switching Regulators www.national.com/switchers Distributors www.national.com/contacts LDOs www.national.com/ldo Quality and Reliability www.national.com/quality LED Lighting www.national.com/led Feedback/Support www.national.com/feedback Voltage Reference www.national.com/vref Design Made Easy www.national.com/easy www.national.com/powerwise Solutions www.national.com/solutions Mil/Aero www.national.com/milaero PowerWise® Solutions Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors SolarMagic™ www.national.com/solarmagic Wireless (PLL/VCO) www.national.com/wireless www.national.com/training PowerWise® Design University THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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