LT1308A/LT1308B High Current, Micropower Single Cell, 600kHz DC/DC Converters FEATURES DESCRIPTION n 5V at 1A from a Single Li-Ion Cell The LT 1308A/LT1308B are micropower, xed frequency n 5V at 800mA in SEPIC Mode from Four NiCd Cells step-up DC/DC converters that operate over a 1V to 10V n Fixed Frequency Operation: 600kHz input voltage range. They are improved versions of the n Boost Converter Outputs up to 34V LT1308 and are recommended for use in new designs. n Starts into Heavy Loads The LT1308A features automatic shifting to power sav- n Automatic Burst Mode Operation at ing Burst Mode operation at light loads and consumes Light Load (LT1308A) just 140A at no load. The LT1308B features continuous n Continuous Switching at Light Loads (LT1308B) switching at light loads and operates at a quiescent cur- n Low V Switch: 300mV at 2A rent of 2.5mA. Both devices consume less than 1A in CESAT n shutdown. Pin-for-Pin Upgrade Compatible with LT1308 n Lower Quiescent Current in Shutdown: 1A (Max) Low-battery detector accuracy is signi cantly tighter than n Improved Accuracy Low-Battery Detector the LT1308. The 200mV reference is speci ed at 2% Reference: 200mV 2% at room and 3% over temperature. The shutdown pin n Available in 8-Lead SO and 14-Lead TSSOP Packages enables the device when it is tied to a 1V or higher source and does not need to be tied to V as on the LT1308. An IN internal V clamp results in improved transient response C APPLICATIONS and the switch voltage rating has been increased to 36V, n GSM/CDMA Phones enabling higher output voltage applications. n Digital Cameras The LT1308A/LT1308B are available in the 8-lead SO and n LCD Bias Supplies the 14-lead TSSOP packages. n Answer-Back Pagers L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks n GPS Receivers of Linear Technology Corporation. All other trademarks are the property of their respective n owners. Battery Backup Supplies n Handheld Computers TYPICAL APPLICATION Converter Ef ciency L1 95 D1 4.7H V = 3.6V V = 4.2V IN IN 5V 90 1A V SW 85 IN + C1 R1* LBI LBO 80 V = 2.5V 47F IN 309k LT1308B + V = 1.5V IN Li-Ion 75 C2 SHUTDOWN SHDN FB CELL 220F V GND C 70 R2 100k 65 47k 60 100pF 55 C1: AVX TAJC476M010 L1: MURATA LQH6C4R7 50 C2: AVX TPSD227M006 *R1: 887k FOR V = 12V OUT 1 10 100 1000 1308A/B F01a D1: IR 10BQ015 LOAD CURRENT (mA) Figure 1. LT1308B Single Li-Ion Cell to 5V/1A DC/DC Converter 1308A/B F01b 1308abfb 1 EFFICIENCY (%)LT1308A/LT1308B ABSOLUTE MAXIMUM RATINGS (Note 1) V , SHDN, LBO Voltage ........................................... 10V Operating Temperature Range IN SW Voltage .............................................. 0.4V to 36V Commercial............................................. 0C to 70C FB Voltage ......................................................... V + 1V Extended Commerial (Note 2) ............ 40C to 85C IN V Voltage ................................................................. 2V Industrial ........................................... 40C to 85C C LBI Voltage ................................................. 0.1V to 1V Storage Temperature Range .................. 65C to 150C Current into FB Pin ............................................... 1mA Lead Temperature (Soldering, 10 sec) ................. 300C PIN CONFIGURATION TOP VIEW V 1 LBO 14 C FB 2 LBI 13 TOP VIEW SHDN 3 V 12 IN V 1 8 LBO C GND 4 V 11 IN FB 2 7 LBI GND 5 SW 10 SHDN 3 6 V IN GND 6 SW 9 GND 4 5 SW GND 7 SW 8 S8 PACKAGE F PACKAGE 8-LEAD PLASTIC SO 14-LEAD PLASTIC TSSOP T = 125C, = 190C/W JMAX JA (NOTE 6) T = 125C, = 80C/W JMAX JA OBSOLETE, FOR INFORMATION PURPOSES ONLY Contact Linear Technology for Potential Replacement ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT1308ACS8 PBF LT1308ACS8 TRPBF 1308A 8-Lead Plastic SO 0C to 70C LT1308AIS8 PBF LT1308AIS8 TRPBF 1308AI 8-Lead Plastic SO 40C to 85C LT1308BCS8 PBF LT1308BCS8 TRPBF 1308B 8-Lead Plastic SO 0C to 70C LT1308BIS8 PBF LT1308BIS8 TRPBF 1308BI 8-Lead Plastic SO 40C to 85C LT1308ACF PBF LT1308ACF TRPBF LT1308ACF 14-Lead Plastic TSSOP 0C to 70C LT1308BCF PBF LT1308BCF TRPBF LT1308BCF 14-Lead Plastic TSSOP 0C to 70C LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT1308ACS8 LT1308ACS8 TR 1308A 8-Lead Plastic SO 0C to 70C LT1308AIS8 LT1308AIS8 TR 1308AI 8-Lead Plastic SO 40C to 85C LT1308BCS8 LT1308BCS8 TR 1308B 8-Lead Plastic SO 0C to 70C LT1308BIS8 LT1308BIS8 TR 1308BI 8-Lead Plastic SO 40C to 85C LT1308ACF LT1308ACF TR LT1308ACF 14-Lead Plastic TSSOP 0C to 70C LT1308BCF LT1308BCF TR LT1308BCF 14-Lead Plastic TSSOP 0C to 70C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. For more information on lead free part marking, go to: