Dual 750 mA LED Flash Driver 2 with I C-Compatible Interface Data Sheet ADP1660 FEATURES FUNCTIONAL BLOCK DIAGRAM INPUT VOLTAGE = 2.7V TO 5.0V Ultracompact solution Small, 2 mm 1.7 mm, 12-ball WLCSP package 10F Smallest footprint, 1 mm height, 1 H power inductor 1.0H LED current source for local LED grounding Simplified routing to and from LEDs VIN SW TORCH/ Improved LED thermal dissipation GPIO VOUT TxMASK Synchronous 3 MHz PWM boost converter, no external diode 10F High efficiency: 90% peak ADP1660 Reduces high levels of input battery current during flash LED1 STROBE UP TO Limits battery current drain in torch mode 750mA 2 I C programmable SCL LED2 UP TO SDA Currents up to 750 mA in flash mode per LED 750mA EN SGND PGND with 7% accuracy for currents above 100 mA Torch mode Programmable dc battery current limit Figure 1. Programmable flash timer up to 1600 ms Low battery mode to reduce LED current automatically Li-ION+ Device control 2 I C-compatible control registers L1 External STROBE and torch input pins PGND Transmitter mask (TxMASK) input Safety features Thermal overload protection C2 Inductor fault detection INDUCTOR DIGITAL LED short-circuit/open-circuit protection INPUT/ OUTPUT APPLICATIONS 2 Camera-enabled cellular phones and smartphones AREA = 16.4mm LED1 LED2 Digital still cameras, camcorders, and PDAs Figure 2. PCB Layout GENERAL DESCRIPTION The ADP1660 is a very compact, highly efficient, dual white LED A programmable dc battery current limit safely maximizes flash driver for high resolution camera phones that improves LED current for all LED forward voltage and battery voltage picture and video quality in low light environments. The device conditions. integrates a programmable 1.5 MHz or 3.0 MHz synchronous A TxMASK input enables fast reduction of the flash LED 2 inductive boost converter, an I C-compatible interface, and two currents and battery current during a power amplifier current 750 mA current sources. The high switching frequency enables 2 burst. The I C-compatible interface can be used to program the use of a tiny, 1 mm high, low cost, 1 H power inductor, and timers and currents and to read back status bits for operation the parallel current sources permit LED cathode grounding for monitoring and safety control. thermally enhanced, low EMI, and compact layouts. The ADP1660 comes in a compact, 12-ball, 0.5 mm pitch The LED driver maximizes efficiency over the entire battery voltage WLCSP package and operates within specification over the range to maximize the input-power-to-LED-power conversion full 40C to +125C junction temperature range. and minimize battery current draw during flash events. Rev. 0 Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 2012 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Technical Support www.analog.com Trademarks and registered trademarks are the property of their respective owners. C1 11018-002 11018-001ADP1660 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Fixed 5 V Output Mode ............................................................. 13 Applications ....................................................................................... 1 Frequency Foldback ................................................................... 13 Functional Block Diagram .............................................................. 1 Low Battery LED Current Foldback ........................................ 13 General Description ......................................................................... 1 Battery Input DC Current Limit .............................................. 14 Revision History ............................................................................... 2 Fixed 5 V Output Mode with Torch ........................................ 15 Specifications ..................................................................................... 3 Safety Features ................................................................................. 16 Recommended Specifications: Input and Output Capacitance Short-Circuit Fault ..................................................................... 16 and Inductance ............................................................................. 4 Overvoltage Fault ....................................................................... 16 2 I C-Compatible Interface Timing Specifications ..................... 5 Dynamic Overvoltage Protection Mode ................................. 16 Absolute Maximum Ratings ............................................................ 6 Timeout Fault .............................................................................. 16 Thermal Data ................................................................................ 6 Overtemperature Fault .............................................................. 16 Thermal Resistance ...................................................................... 6 Current Limit .............................................................................. 16 ESD Caution .................................................................................. 6 Input Undervoltage .................................................................... 16 Pin Configuration and Function Descriptions ............................. 7 Soft Start ...................................................................................... 16 Typical Performance Characteristics ............................................. 8 Reset Using the Enable (EN) Pin ............................................. 16 Theory of Operation ...................................................................... 10 Clearing Faults ............................................................................ 16 White LED Driver ...................................................................... 10 2 I C Interface .................................................................................... 17 Modes of Operation ................................................................... 10 Register Map ................................................................................... 18 Assist Light Mode ....................................................................... 11 Register Details ........................................................................... 18 Flash Mode .................................................................................. 11 Applications Information .............................................................. 24 Assist to Flash Mode .................................................................. 12 External Component Selection ................................................ 24 Torch Mode ................................................................................. 12 PCB Layout ...................................................................................... 25 Torch to Flash Mode .................................................................. 12 Outline Dimensions ....................................................................... 26 TxMASK Operation ................................................................... 12 Ordering Guide .......................................................................... 26 Independent Trigger Modes ...................................................... 13 REVISION HISTORY 10/12Revision 0: Initial Version Rev. 0 Page 2 of 28