低压输入， 3-3.3V / 5V /可调输出DC- DC同步整流转换器 LOW VOLTAGE INPUT, 3-3.3V/5V/ADJUSTABLE OUTPUT DC-DC CONVERTER WITH SYNCHRONOUS RECTIFIER
DESCRIPTION
The ST777/778/779 are dc-dc converters that step-up from low voltage inputs requiring only three external components, an inductor typically 22µH and two capacitors. The device include a Sinchronous Rectifier that eliminates the need for an external catch diode, and allows regulation even when the input is greater than the output.
Unlike others step-up DC-DC converters the ST777/778/779’s Sinchronous Rectifier turns off in the shutdown mode, fully disconnecting the output from the source. This eliminates the current drain associated with conventional step-up converters when off or in shutdown. Supply current is 270µA under no load and only 20µA in stand by mode.
■ 1V TO 6V INPUT GUARANTEES START-UP UNDER LOAD
■ MAXIMUM OUTPUT CURRENT OF 300mA
778 OR 779 ADJUSTED TO 3V
■ LOAD FULLY DISCONNECTED IN SHUTDOWN
■ TYPICAL EFFICIENCY OF 82%
■ INTERNAL 1A POWER SWITCH AND SYNCHRONOUS RECTIFIER
■ ADJUSTABLE CURRENT LIMIT ALLOWS LOW-COST INDUCTORS
■ SUPPLY CURRENT OF 270µA NO LOAD
■ SHUTDOWN SUPPLY CURRENT 20µA
■ PACKAGE AVAILABLE: DIP-8 AND SO-8