LT1304/LT1304-3.3/LT1304-5 Micropower DC/DC Converters with Low-Battery Detector Active in Shutdown FEATURES DESCRIPTION n 5V at 200mA from Two Cells The LT 1304 is a micropower step-up DC/DC converter n 10A Quiescent Current in Shutdown ideal for use in small, low voltage, battery-operated sys- n Operates with V as Low as 1.5V tems. The devices operate from a wide input supply range IN n Low-Battery Detector Active in Shutdown of 1.5V to 8V. The LT1304-3.3 and LT1304-5 generate n Low Switch V : 370mV at 1A Typical regulated outputs of 3.3V and 5V and the adjustable CESAT n 120A Quiescent Current in Active Mode LT1304 can deliver output voltages up to 25V. Quiescent n Switching Frequency Up to 300kHz current, 120A in active mode, decreases to just 10A in n Programmable Peak Current with One Resistor shutdown with the low-battery detector still active. Peak n 8-Lead SO Package switch current, internally set at 1A, can be reduced by adding a single resistor from the I pin to ground. The U LIM APPLICATIONS high speed operation of the LT1304 allows the use of small, surface-mountable inductors and capacitors. The n 2-, 3-, or 4-Cell to 5V or 3.3V Step-Up LT1304 is available in an 8-lead SO package. n Portable Instruments , LTC and LT are registered trademarks of Linear Technology Corporation. n Bar Code Scanners n Palmtop Computers n Diagnostic Medical Instrumentation n Personal Data Communicators/Computers TYPICAL APPLICATION 2-Cell to 5V Step-Up Converter with Low-Battery Detect Efficiency D1** 22H* 90 34 499k V SW IN 80 8 1 5V LBI SENSE 200mA + + LT1304-5 100k 100F 70 2 CELLS 100F 604k 6 2 LBO NC I LBO LIM LOW WHEN SHDN GND 60 V < 2.2V BAT 7 5 SHUTDOWN V = 3.3V IN 50 V = 2.5V IN V = 1.8V IN * SUMIDA CD54-220 1304 TA01 **1N5817 40 0.1 1 10 100 500 LOAD CURRENT (mA) 1304 TA02 1 EFFICIENCY (%) U ULT1304/LT1304-3.3/LT1304-5 ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION V Voltage ................................................................ 8V IN ORDER PART SW Voltage ............................................... 0.4V to 25V NUMBER TOP VIEW FB Voltage (LT1304)...................................... V + 0.3V IN LT1304CS8 Sense Voltage (LT1304-3.3/LT1304-5) ..................... 8V LBI 1 8 FB (SENSE)* LT1304CS8-3.3 I Voltage .............................................................. 5V LBO SHDN 2 7 LIM LT1304CS8-5 SHDN Voltage ............................................................ 6V V 3 6 I IN LIM LBI Voltage ............................................................... V SW 4 5 GND IN LBO Voltage ............................................................... 8V S8 PART MARKING S8 PACKAGE 8-LEAD PLASTIC SO Maximum Power Dissipation ............................. 500mW *FIXED OUTPUT VERSION 1304 Junction Temperature.......................................... 125C T = 125C, = 150C/W JMAX JA 13043 Operating Temperature Range ..................... 0C to 70C 13045 Storage Temperature Range ................. 65C to 150C Lead Temperature (Soldering, 10 sec).................. 300C Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS V = 2V, V = 2V unless otherwise noted. IN SHDN PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Operating Voltage l 1.5 1.65 V Operating Voltage Range l 8V Quiescent Current V = 2V, Not Switching l 120 200 A SHDN Quiescent Current in Shutdown V = 0V, V = 2V l 715 A SHDN IN V = 0V, V = 5V l 27 50 A SHDN IN Comparator Trip Point LT1304 l 1.22 1.24 1.26 V FB Pin Bias Current LT1304 l 10 25 nA Sense Pin Leakage in Shutdown V = 0V, Fixed Output Versions l 0.002 1 A SHDN Output Sense Voltage LT1304-3.3 l 3.17 3.3 3.43 V LT1304-5 l 4.80 5.05 5.25 V Line Regulation 1.8V V 8V l 0.04 0.15 %/V IN LBI Input Threshold Falling Edge l 1.10 1.17 1.25 V LBI Bias Current l 620 nA LBI Input Hysteresis l 35 65 mV LBO Output Voltage Low I = 500A l 0.2 0.4 V SINK LBO Output Leakage Current LBI = 1.5V, LBO = 5V l 0.01 0.1 A SHDN Input Voltage High l 1.4 V SHDN Input Voltage Low l 0.4 V SHDN Pin Bias Current V = 5V l 58 A SHDN V = 0V l 5 2 A SHDN Switch OFF Time l 1 1.5 2 s Switch ON Time Current Limit Not Asserted l 468 s Maximum Duty Cycle Current Limit Not Asserted l 76 80 88 % Peak Switch Current I Pin Open, V = 5V 0.8 1 1.2 A LIM IN 20k from I to GND 500 mA LIM 2 U W U W U WW