19-0186; Rev 2; 7/96
NUAL KIT MA ATION U EET L H A S V E TA WS DA FOLLO
Low-Voltage Input, 3V/3.3V/5V/ Adjustable Outp...
19-0186; Rev 2; 7/96
NUAL KIT MA ATION U EET L H A S V E TA WS DA FOLLO
Low-
Voltage Input, 3V/3.3V/5V/ Adjustable Output, Step-Up DC-DC Converters
____________________________Features
o 1V to 4.5V Input Guarantees Start-Up Under Load o Up to 210mA Output o Load Fully Disconnected in Shutdown o 82% Efficiency o Output in Regulation with Input
Voltage above Output
Voltage o Internal 1A Power Switch and Active Rectifier o Adjustable Current Limit Allows Low-Cost Inductors o 190µA No Load Supply Current o 20µA Shutdown Supply Current o 3V/3.3V (MAX778L), 5V (MAX777L), and Adjustable (MAX779L) Output
Voltage
_______________General Description
The MAX777L/MAX778L/MAX779L are pulse-skipping DC-DC converters that step up from low-
voltage inputs (1V guaranteed). They require only three external components—an inductor (typically 22µH) and two
capacitors. The MAX777L delivers a 5V output, the MAX778L generates pin-selectable
voltages of 3.0V or 3.3V, and the MAX779L output can be adjusted from 2.5V to 6V through an external resistive divider. The devices include an Active RectifierTM that eliminates the need for an external catch diode, and permits regulation even when the input is greater than the output. Also, unlike those in other step-up converters, the MAX777L/MAX778L/MAX779L’s Active RectifierTM turns off in the shutdown mode, disconnecting the output from the source. This eliminates the current drain associated with conventional step-up converters when off or in shutdown. High...