LT1317CMS8#PBF Analog Devices

LT1317/LT1317B Micropower, 600kHz PWM DC/DC Converters DESCRIPTION FEATURES n 100A Quiescent Current The LT 1317/LT1317B are micropower, fixed frequency n Operates with V as Low as 1.5V step-up DC/DC converters that operate over a wide input IN n 600kHz Fixed Frequency Operation voltage range of 1.5V to 12V. The LT1317 features auto- TM n Starts into Full Load matic shifting to power saving Burst Mode operation at n Low-Battery Detector Active in Shutdown light loads. High efficiency is maintained over a broad n Automatic Burst Mode Operation at 300A to 200mA load range. Peak switch current during Light Load (LT1317) Burst Mode operation is kept below 250mA for most n Continuous Switching at Light Loads (LT1317B) operating conditions which results in low output ripple n Low V Switch: 300mV at 500mA voltage, even at high input voltages. The LT1317B does CESAT n Pin for Pin Compatible with the LT1307/LT1307B not shift into Burst Mode operation at light loads, eliminat- ing low frequency output ripple at the expense of light load U efficiency. APPLICATIONS The LT1317/LT1317B contain an internal low-battery de- n Cellular Telephones tector with a 200mV reference that stays alive when the n Cordless Telephones device goes into shutdown. n Pagers No-load quiescent current of the LT1317 is 100A and n GPS Receivers shuts down to 30A. The internal NPN power switch n Battery Backup handles a 500mA current with a voltage drop of just n Portable Electronic Equipment 300mV. n Glucose Meters n Diagnostic Medical Instrumentation The LT1317/LT1317B are available in MS8 and SO-8 packages. , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a trademark of Linear Technology Corporation. TYPICAL APPLICATION 2-Cell to 3.3V Converter Efficiency L1 D1 10H 90 2.2V 3V IN IN + C1 V SW 80 IN 47F 3.3V 1.65V IN LBI FB 200mA LT1317 R1 1M 2 70 SHUTDOWN SHDN LBO 1% CELLS V GND C + C2 47F 60 R2* R C 604k 33k 1% C C 50 3.3nF D1: MBR0520 1317 F01 40 L1: SUMIDA CD43-100 0.3 1 10 100 1000 * FOR 5V OUTPUT, R2 = 332k, 1% LOAD CURRENT (mA) Figure 1. 2-Cell to 3.3V Boost Converter 1317 TA01 1 EFFICIENCY (%) U ULT1317/LT1317B O (Note 1) ABS LUTEXAI U RATI GS V , LBO Voltage..................................................... 12V Junction Temperature.......................................... 125C IN SW Voltage ............................................... 0.4V to 30V Operating Temperature Range FB Voltage .................................................... V + 0.3V Commercial ........................................... 0C to 70C IN V Voltage ................................................................ 2V Industrial ............................................ 40C to 85C C LBI Voltage ............................................ 0V V 1V Storage Temperature Range ................ 65C to 150C LBI SHDN Voltage ............................................................ 6V Lead Temperature (Soldering, 10 sec)................ 300C PACKAGE/ORDER I FOR ATIO ORDER PART ORDER PART TOP VIEW NUMBER NUMBER TOP VIEW V 1 8 LBO C V 1 8 LBO C LT1317CMS8 LT1317CS8 FB LBI FB 2 7 LBI 2 7 SHDN 3 6 V LT1317BCMS8 LT1317BCS8 IN SHDN 3 6 V IN GND 4 5 SW LT1317IS8 GND 4 5 SW MS8 PACKAGE LT1317BIS8 8-LEAD PLASTIC MSOP S8 PACKAGE T = 125C, = 160C/W JMAX JA 8-LEAD PLASTIC SO MS8 PART MARKING S8 PART MARKING T = 125C, = 120C/W JMAX JA 1317 LTHA 1317B LTHB 1317I 1317BI Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS Commercial Grade V = 2V, V = 2V, T = 25C, unless otherwise noted. IN SHDN A SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS I Quiescent Current Not Switching, V = 2V (LT1317) l 100 160 A Q SHDN V = 0V (LT1317/LT1317B) l 25 40 A SHDN V = 2V, Switching (LT1317B) 4.8 6.5 mA SHDN V = 2V, Switching (LT1317B) l 7.5 mA SHDN V Feedback Voltage 1.22 1.24 1.26 V FB l 1.20 1.24 1.26 V I FB Pin Bias Current (Note 2) l 12 60 nA B Input Voltage Range l 1.5 12 V g Error Amp Transconductance I = 5A l 70 140 240 mhos m A Error Amp Voltage Gain 700 V/V V Maximum Duty Cycle l 80 85 % Switch Current Limit (Note 3) V = 2.5V, Duty Cycle = 30% 710 800 1300 mA IN V = 2.5V, Duty Cycle = 30% l 660 1350 mA IN Burst Mode Operation Switch Current Limit Duty Cycle = 30% (LT1317) 275 mA f Switching Frequency l 520 620 720 kHz OSC 2 U WU U W W W