LT1303/LT1303-5 Micropower High Efficiency DC/DC Converters with Low-Battery Detector Adjustable and Fixed 5V FEATURES DESCRIPTION n 5V at 200mA from a 2V Input The LT 1303/LT1303-5 are micropower step-up high TM n Supply Voltage As Low As 1.8V efficiency DC/DC converters using Burst Mode opera- n Up to 88% Efficiency tion. They are ideal for use in small, low-voltage battery- n 120A Quiescent Current operated systems. The LT1303-5 accepts an input voltage n Low-Battery Detector between 1.8V and 5V and converts it to a regulated 5V. The n Low V Switch: 170mV at 1A Typ LT1303 is an adjustable version that can supply an output CESAT n Uses Inexpensive Surface Mount Inductors voltage up to 25V. Quiescent current is only 120A from n 8-Lead PDIP or SO Package the battery and the shutdown pin further reduces current to 10A. The low-battery detector provides an open- U collector output that goes low when the input voltage APPLICATIONS drops below a preset level. The on-chip NPN power switch n EL Panel Drivers has a low 170mV saturation voltage at a switch current n 2-Cell and 3-Cell to 5V Conversion of 1A. The LT1303/LT1303-5 are available in 8-lead PDIP n Palmtop Computers or SO packages, easing board space requirements. n Portable Instruments For higher output current, please see the LT1305 or n Bar-Code Scanners LT1302. n PDAs , LTC and LT are registered trademarks of Linear Technology Corporation. n Wireless Systems Burst Mode is a trademark of Linear Technology Corporation. TYPICAL APPLICATION 5V Output Efficiency L1 1N5817 22H 90 V = 4V IN 316k 80 1% V SW IN V = 2V IN V = 2.5V V , 5V IN OUT LBI SENSE 200mA 70 + V = 3V IN 412k LT1303-5 100F 2 CELLS 100k 1% LOW BATTERY 60 SHUTDOWN SHDN LBO GOES LOW AT V = 2.2V + BAT GND PGND 100F 50 40 L1 = SUMDIA CD54-220 LT1303 TA02 30 0.1 1 10 100 1000 Figure 1. 2-Cell to 5V DC/DC Converter with Low-Battery Detect LOAD CURRENT (mA) LT1303 TA01 1 EFFICIENCY (%) U ULT1303/LT1303-5 ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION V Voltage .............................................................. 10V IN ORDER PART TOP VIEW SW1 Voltage ............................................................ 25V NUMBER GND 1 8 PGND Sense Voltage (LT1303-5) ....................................... 20V LBO 2 7 SW LT1303CN8 FB Voltage (LT1303) ................................................ 10V SHDN 3 6 V IN LT1303CS8 Shutdown Voltage ................................................... 10V FB (SENSE)* 4 5 LBI LT1303CN8-5 LBO Voltage ............................................................. 10V LT1303CS8-5 N8 PACKAGE LBI Voltage .............................................................. 10V 8-LEAD PDIP Maximum Power Dissipation ............................. 500mW S8 PACKAGE S8 PART MARKING 8-LEAD PLASTIC SO Operating Temperature Range ..................... 0C to 70C *FIXED VERSION 1303 Storage Temperature Range ................. 65C to 150C T = 100C, = 130C/W (N8) JMAX JA 13035 Lead Temperature (Soldering, 10 sec).................. 300C T = 100C, = 150C/W (S8) JMAX JA Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS T = 25C, V = 2.0V, unless otherwise noted. A IN SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS I Quiescent Current V = 0.5V, V = 5V, V = 5.5V l 120 200 A Q SHDN SEL SENSE V = 1.8V l 715 A SHDN V Input Voltage Range 1.8 1.55 V IN l 2.0 V Feedback Voltage LT1303 l 1.22 1.24 1.26 V Output Sense Voltage LT1303-5 l 4.8 5.0 5.2 V Comparator Hysteresis LT1303 (Note 1) l 6 12.5 mV Output Hysteresis LT1303-5 (Note 1) l 22 50 mV Feedback Pin Bias Current LT1303, V = 1V l 720 nA FB Oscillator Frequency Current Limit Not Asserted 120 155 185 kHz Oscillator TC 0.2 %/C DC Maximum Duty Cycle l 75 86 95 % t Switch On Time Current Limit Not Asserted 5.6 s ON Output Line Regulation 1.8V < V < 6V l 0.06 0.15 %/V IN V Switch Saturation Voltage I = 700mA l 130 200 mV CESAT SW Switch Leakage Current V = 5V, Switch Off l 0.1 10 A SW Peak Switch Current V = 2V l 0.75 1.0 1.25 A IN V = 5V 0.65 0.9 1.15 A IN LBI Trip Voltage l 1.21 1.24 1.27 V LBI Input Bias Current V = 1V l 720 nA LBI LBO Output Low I = 100A l 0.11 0.4 V LOAD LBO Leakage Current V = 1.3V, V = 5V l 0.1 5 A LBI LBO V Shutdown Pin High l 1.8 V SHDNH V Shutdown Pin Low 0.5 V SHDNL I Shutdown Pin Bias Current V = 5V l 8.0 20 A SHDN SHDN V = 2V l 3.0 A SHDN V = 0V l 0.1 1 A SHDN The l denotes specifications which apply over the 0C to 70C operating Note 1: Hysteresis specified is DC. Output ripple may be higher if output temperature range. capacitance is insufficient or capacitor ESR is excessive. 2 U W U W U WW