LT1317B

Features:

*100A Quiescent Current
*Operates with V_IN as Low as 1.5V
*600kHz Fixed Frequency Operation
*Starts into Full Load
*Low-Battery Detector Active in Shutdown
*Automatic Burst Mode Operation at
*Light Load (LT1317)
*Continuous Switching at Light Loads (LT1317B)
*Low V_CESAT Switch: 300mV at 500mA
*Pin for Pin Compatible with the LT1307/LT1307B


Application

*Cellular Telephones
*Cordless Telephones
*Pagers
*GPS Receivers
*Battery Backup
*Portable Electronic Equipment
*Glucose Meters
*Diagnostic Medical Instrumentation


Pinout




Specifications

V_IN , LBO Voltage.....................................................  12V
SW Voltage................................................ 0.4V to 30V
FB Voltage .....................................................V_IN  + 0.3V
V_C Voltage.................................................................  2V
LBI Voltage...........................................  0V V_LBI 1V
SHDN Voltage............................................................. 6V
Junction Temperature.......................................... 125 ^oC
Operating Temperature Range
Commercial...............................................  0 ^oC to 70 ^oC
Industrial...............................................40 ^oC to 85 ^oC
Storage Temperature Range................ 65^oC to 150^oC
Lead Temperature (Soldering, 10 sec)................  300^oC


Description

The LT^@ 1317/LT1317B are micropower, fixed frequency step-up DC/DC converters that operate over a wide input voltage range of 1.5V to 12V. The LT1317 features auto-TM matic shifting to power saving Burst Mode  operation at light loads. High efficiency is maintained over a broad 300A to 200mA load range. Peak switch current during Burst Mode operation is kept below 250mA for most operating conditions which results in low output ripple voltage, even at high input voltages. The LT1317B does not shift into Burst Mode operation at light loads, eliminating low frequency output ripple at the expense of light load efficiency.


The LT1317/LT1317B contain an internal low-battery detector with a 200mV reference that stays alive when the device goes into shutdown.


No-load quiescent current of the LT1317 is 100A and shuts down to 30A. The internal NPN power switch handles a 500mA current with a voltage drop of just 300mV.


The LT1317/LT1317B are available in MS8 and SO-8 packages.