EVALUATION KIT AVAILABLE MAX77387 Dual-Phase Adaptive DC-DC Step-Up Converter With 2x 1000mA High-Side Current Regulators General Description Benefits and Features The MAX77387 provides a high-efficiency solution for S Input Supply of 2.5V to 5.5V with Full Functionality smartphone camera flash applications by integrating a S Dual-Phase Interleave Step-Up DC-DC Converter dual-phase 2A PWM DC-DC step-up converter and two True Shutdown Output programmable 1A high side, low-dropout LED current 2A Guaranteed Output Current for V > 2.7V IN 2 regulators for flash and torch functions. An I C interface and V P 4.0V OUT provides flexible control of the step-up converter, torch, Adaptive Output Voltage Regulation to Ensure flash mode selection, and torch/flash safety timer dura- Industrys Highest System Efficiency tion settings. Over 90% Peak Efficiency The IC operates down to 2.5V, making it futureproof for 3.125% Minimum Duty Cycle new battery technologies. The step-up converter features Skip Mode Capable an internal switching MOSFET and synchronous rectifier On-Chip Power MOSFET and Synchronous to improve efficiency and minimize external component Rectifier count. Dual-phase operation ensures low output ripple Up to 4MHz PWM Switching Frequency per and provides smallest possible solution size. The IC also Phase includes dual high-side high-current regulators for sup- Small 0.47FH Inductor per Phase porting torch and flash modes. The high-current regula- S High-Side Torch/Flash LED Current Regulator tors can source up to 1A each in flash mode and up to 2 I C Programmable Flash Output Current 250mA each in torch mode. The high-current regulators (15.625mA to 1000mA in 15.625mA Steps) can be combined to drive a single LED up to 2A in flash 2 I C Programmable Torch Output Current mode and up to 500mA in torch mode. The output volt- (3.91mA to 250mA in 3.91mA Steps for Non- age can be adaptively controlled, boosting only as high PWM dimming) (125mA to 1000mA in 125mA as necessary to support the required LED forward volt- Steps for PWM Dimming with Programmable age. Adaptive mode can be used in either flash or torch Duty Cycle from 3.125% to 25% in 3.125% steps) mode and works with both DAC and/or PWM dimming Low-Dropout Voltage (80mV typ) at 1000mA control schemes. This approach reduces IC power dis- 2 S I C-Programmable Flash Safety Timer sipation by optimizing the boost ratio and by minimizing 2 S I C-Programmable Torch Safety Timer and the losses in the current regulators. Optional Disabled Torch Timer The IC includes control for external NTC, dual Tx mask, S Dual Independent TX MASK Inputs for Limiting flash strobe, and torch enable functions. This allows for Flash Current During Tx Events flexible control of the IC. S Open/Shorted LED Detection Additionally, the IC includes MAXFLASH 2.0 function that adaptively reduces flash current during low battery S NTC Monitoring for LED Protection conditions to help prevent system undervoltage lockup. S Overvoltage Protection Other features include shorted LED detection, overvolt- S MAXFLASH 2.0 Preventing System Undervoltage age and thermal shutdown protection, and low-power Lockup standby and shutdown modes. The IC is available in a S Thermal Shutdown Protection 20-bump, 0.4mm pitch WLP package (2.1mm x 1.73mm). S < 1A Shutdown Current Applications S 20-Bump, 0.4mm Pitch 2.1mm x 1.73mm WLP Cell Phones and Smartphones Ordering Information appears at end of data sheet. Tablets Simplified Block Diagram appears at end of data sheet. For related parts and recommended products to use with this part, *Patent protected PCT/US2008/075643. refer to www.maximintegrated.com/MAX77387.related. For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maximintegrated.com. 19-6282 Rev 0 7/12MAX77387 Dual-Phase Adaptive DC-DC Step-Up Converter With 2x 1000mA High-Side Current Regulators TABLE OF CONTENTS General Description .................. 1 Applications .................... 1 Benefits and Features .................. 1 Absolute Maximum Ratings ................ 6 Package Thermal Characteristics................ 6 Electrical Characteristics .................. 6 Typical Operating Characteristics ................ 13 Bump Configuration . 27 Bump Description................... 27 Detailed Description................... 30 Modes of Operation .........................................................................30 Shutdown Mode ..........................................................................30 Standby Mode ...........................................................................30 Active Mode .............................................................................30 Torch Mode .............................................................................30 Flash Mode .............................................................................30 Adaptive Output Voltage Regulation............................................................. 31 Current Regulator Voltage Headroom............................................................ 31 Step-Up Converter .......................................................................... 31 Dual-Phase Operation........................................................................ 31 Skip Mode ................................................................................. 31 Current Sharing .............................................................................32 Switching Frequency Selection .................................................................32 Overvoltage Protection .......................................................................32 True Shutdown..............................................................................32 Soft-Start ..................................................................................32 End of Trigger Event .........................................................................35 Gain Selection ..............................................................................35 Low-Side Current Limit .......................................................................35 Current Regulator LED .......................................................................35 Maxim Integrated 2