MAX1776

19-1975; Rev 2; 7/03 24V, 600mA Internal Switch, 100% Duty Cycle, Step-Down Converter General Description The MAX1776 high-efficiency step-down converter provides an adjustable output voltage from 1.25V to VIN from supply voltages as high as 24V. An internal current-limited 0.4Ω MOSFET delivers load currents up to 600mA. Operation to 100% duty cycle minimizes dropout voltage (240mV at 600mA). The MAX1776 has a low 15µA quiescent current to improve light-load efficiency and conserve battery life. The device draws only 3µA while in shutdown. High switching frequencies (up to 200kHz) allow the use of tiny surface-mount inductors and output capacitors. The MAX1776 is available in an 8-pin µMAX package, which uses half the space of an 8-pin SO. For increased output drive capability, use the MAX1626/ MAX1627 step-down controllers, which drive an external P-channel MOSFET to deliver up to 20W. o Fixed 5V or Adjustable Output o 4.5V to 24V Input Voltage Range o Up to 600mA Output Current o Internal 0.4Ω P-Channel MOSFET o Efficiency Over 95% o 15µA Quiescent Supply Current o 3µA Shutdown Current o 100% Maximum Duty Cycle for Low Dropout o Current-Limited Architecture o Thermal Shutdown o Small 8-µMAX Package Features MAX1776 Applications Notebook Computers Distributed Power Systems Keep-Alive Supplies Hand-Held Devices PART MAX1776EUA Ordering Information TEMP RANGE -40°C to +85°C PIN-PACKAGE 8 µMAX Typical Operating Circuit TOP VIEW SHDN IN VIN Pin Configuration ILIM MAX1776...