SSPP77664488 LLooww RReeffeerreennccee HHiigghh EEffffiicciieennccyy BBoooosstt RReegguullaattoorr November 2012 Rev. 2.0.0 GENERAL DESCRIPTION APPLICATIONS The SP7648 is an ultra-low quiescent current, LED Driver high efficiency step-up DC-DC converter ideal Camera Flash for single cell Li-Ion or dual cell alkaline battery applications to drive various LEDs. The Handheld Portable Devices SP7648 combines low quiescent current and excellent light-load efficiency of PFM control. FEATURES The SP7648 features synchronous rectification, a 0.3 charging switch, an anti-ringing True Shutdown inductor switch, under-voltage lockout and 700mA Output Current at 3.3V Input programmable inductor peak current. The 4.2V output device can be shut down by a 1nA active LOW shutdown pin. A very low 0.288V reference 92% Efficiency from 2.7V to 3.3V IN OUT voltage is optimized for driving a constant 2.7V to 4.5V Wide Input Voltage Range current load. 5V Fixed or Adjustable Output 0.3 Switch Integrated Synchronous Rectifier:0.3 Anti-Ringing Switch Technology Programmable Inductor Peak Current Logic Shutdown Control Low 0.8V or 0.288V Reference Voltage Small 10-pin DFN and MSOP Package TYPICAL APPLICATION DIAGRAM Fig. 1: SP7648 Application Diagram Exar Corporation www.exar.com 48720 Kato Road, Fremont CA 94538, USA Tel. +1 510 668-7000 Fax. +1 510 668-7001 SSPP77664488 LLooww RReeffeerreennccee HHiigghh EEffffiicciieennccyy BBoooosstt RReegguullaattoorr ABSOLUTE MAXIMUM RATINGS OPERATING RATINGS These are stress ratings only and functional operation of Input Voltage Range V ............................ 2.7V to 4.5V BATT the device at these ratings or any other above those Ambient Temperature Range ................... -40C to +85C indicated in the operation sections of the specifications Thermal Resistance ...................................................... below is not implied. Exposure to absolute maximum (DFN-10) ............................................... 40.5C/W JA rating conditions for extended periods of time may affect JA (MSOP-10) .......................................... 214.0C/W reliability. LX, Vo, V , FLASHOUT, FB to GND pin ......... -0.3 to 6.0V BATT SHDN, FLASH................................... -0.3V to V +1.0V BATT VO, GND, LX Current ................................................ 2A Reverse V Current .......................................... 220mA BATT Forward V Current.......................................... 500mA BATT Storage Temperature .............................. -65C to 150C ESD Rating (HBM - Human Body Model) .................. 1.5kV ELECTRICAL SPECIFICATIONS Specifications with standard type are for an Operating Ambient Temperature of T = 27C only limits applying over the full A Operating Ambient Temperature range are denoted by a . Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at T = 27C, and are provided A for reference purposes only. Unless otherwise indicated, V = V = 3.6V, V = ZeroV, I = 0mA, V = 5.0V, BATT SHDN FB LOAD OUT T = 40C to 85C. A Parameter Min. Typ. Max. Units Conditions Input Voltage Operating Range After Startup 2.7 - 4.5 V V BATT Output Voltage Range V 27 - 5.5 V OUT Under Voltage Lock-out UVLO 0.5 0.61 0.7 V Output Voltage V 5.0 5.4 V Internal Feedback Divider O 4.6 Shutdown Current into V , I 1 500 nA V = ZeroV O SDO - SHDN Shutdown Current into V , I - 250 750 nA V = ZeroV, V = 2.7V BATT SDB SHDN BATT Efficiency 92 - % V = 2.7V, I = 200mA, R = 2k BATT OUT LIM 650 800 1000 R = 2k, I = 1600/R LIM PK LIM Inductor Peak Current Limit, I mA PK 1600 R = 1k, I = 1600/R LIM PK LIM 800 V = 2.7V, R =1k BATT LIM Output Current (Note 2) 400 mA V = 2.7V, R =2k BATT LIM 200 V = 2.7V, R = 4k BATT LIM Minimum Off-Time Constant K 1.0 1.5 V*s K T (V - V ) OFF 0.5 OFF OFF OUT BATT Maximum On-Time Constant K 3.5 5.0 V*s K T (V ) ON 2.0 ON ON BATT Enable Valid to Output Stable 300 500 s I = 1mA LOAD (Note 3) NMOS Switch Resistance 0.30 0.6 I = 100mA NMOS PMOS Switch Resistance 0.30 0.6 I = 100mA PMOS 0.76 0.8 0.84 External feedback Flash = 0 FB Set Voltage, V V FB 0.288 0.310 External feedback Flash = 1 0.266 FB Input Current 1 100 nA V =1.3V - FB SHDN Input Voltage V (Note 1) IL 0.5 V V = 2.7V BATT SHDN Input Voltage V (Note 1) 2.0 IH SHDN Input Current 1 100 nA LX Pin Leakage 3 A FLASH Threshold V 0.4 IL V FLASH Threshold V 1.0 IH Note 1: SHDN must transition faster than 1V/100mS for proper operation. Note 2: Output Current I = (VIN/VOUT) x Efficiency x (Inductor Peak Current - Inductor Ripple Current)/2 2012 Exar Corporation 2/13 Rev. 2.0.0