The LT 1106 is the industry's first DC/DC converter designed for use on Type I and Type II PCMCIA cards. The device senses the VPP1 and VPP2 lines at the PCMCIA socket and generates a regulated 12V, 60mA programming supply if the socket does not provide it. Internal logic simplifies the interface to PCMCIA card microcontrollers. One input selects a 12V or 5V regulated output, while another input controls micropower shutdown. Two logic outputs indicate when the selected programming voltage is valid and whether the input supply is 3.3V or 5V. The regulator features Burst ModeTM operation with a 0.5A, 300mV switch for efficiency up to 85%. High frequency 500kHz switching permits the use of small value, flat inductors that fit neatly on PCMCIA cards. The device requires just 1F of output capacitance. Quiescent current is 750A which drops to 350A when the card runs off the socket supply. The shutdown pin reduces supply current to only 10A. The device includes a soft start feature which limits supply current transients when the card is inserted into a hot socket.