The LT 1309 is a 500kHz micropower DC/DC converter for Flash Memory. The regulator features Burst ModeTM operation with a 0.5A, 300mV switch, enabling 85% efficiency at the fixed 12V output. High frequency operation permits the use of small value, and therefore small size, surface mount inductors and capacitors. The LT1309 comes in an 8-lead SO package allowing extremely compact PC board layouts. These features make the device attractive for PCMCIA cards, cellular phones and other applications where PC board space is limited. Quiescent current is 650A decreasing to 9A when the part shuts down. The device includes a soft start feature which limits supply current transients during turn-on. The LT1309 contains a VPP VALID comparator with a logic output that goes low when the output voltage is ready to program 12V Flash Memory. This comparator simplifies the interface to external control logic.