DESCRIPTION
SCHEMATIC DIAGRAM VIN 100µF 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. Supply current is 270µA under no load and only 20µA in stand by mode. 22µH RLIM 2 IN DELAY TIMER 1 5 ILIM LX ACTIVE RECTIFIER tOFF SWITCH DRIVER DELAY TIMER OUT 6 VO 100µF tON 1 : N RECTIFIER CONTROL PGND 4 SEL 8 VREF 1.25V 7 SHDN SHUTDOWN CONTROL AGND 3 October 2002 1/11 ST777/778/779 ABSOLUTE MAXIMUM RATINGS
Symbol VCC LX OUT, SHDN AGND to PGND FB PTOT TSTG TOP Parameter DC Input Voltage to GND Switch off Pin Voltage Switch on Pin Voltage Output, Shutdown Voltage Analog and Power Ground FB Pin Voltage Continuous Power Dissipation (at TA = 85°C) DIP-8 Continuous Power Dissipation (at TA = 85°C) SO-8 Storage Temperature Range Operating Ambient Temperature Range Value -0.3 to +7 -0.3 to +7 30 sec short to IN or OUT -0.3 to +7 -0.3 to +0.3 -0.3 to (OUT+0.3) 550 344 -40 to 150 0 to 85 Unit V V V V V mW °C °C ABSOLUTE MAXIMUM RATINGS
are those values beyond which damage to the device may occur.
STMicroelectronics
