MAX879

19-0204; Rev 1; 5/94 NUAL KIT MA ATION U EET L H A S V A E T WS DA FOLLO 5V/3.3V/3V/Adjustable-Output, Step-Up/Step-Down DC-DC Converters ____________________________Features o Regulates from Inputs Above & Below the Output o 1V to 6.2V Supply-Voltage Range o Internal 1A Active Rectifier with Input-to-Output Disconnect in Shutdown o Up to 210mA Load Currents, Guaranteed o 85% Efficiency o Only 3 External Components o Adjustable Current Limit o 195µA Quiescent Supply Current o 20µA Shutdown Supply Current o 3V/3.3V/5V and Adjustable Output Voltage Versions o Available in 8-Pin DIP and SO Packages _______________General Description The MAX877/MAX878/MAX879 are pulse-skipping, stepup/step-down DC-DC converters that provide a regulated output from inputs both above and below the output. They require only three external components—an inductor (typically 22µH) and two filter capacitors. The MAX877 delivers a regulated 5V output from 2.5V to 6.2V inputs. The MAX878 generates pin-selectable voltages of 3.0V or 3.3V from 1.5V to 6.2V inputs. The MAX879 output can be adjusted from 2.5V to 6V via an external resistor divider from 2.5V to 6.2V inputs. A unique high-power, internal, synchronous rectifier design (Active Rectifier™) enables the devices to regulate in a switched linear mode if the input voltage is higher than the desired output voltage. When the input voltage falls below the output voltage, the MAX877/MAX878/MAX879 will smoothly switch into a pulse-skipping boost mode and...