The MAX5096/MAX5097 easy-to-use, Dual ModeTM, DC-DC converters operate as LDO (low dropout) or switch-mode buck converters. At a high output load, the converters operate as high-efficiency pulse-widthmodulated (PWM) switch-mode converters and reduce the power dissipation. The devices switch to a low-quiescent-current (IQ) LDO mode of operation at light load. During the key-off condition, the system's microcontroller drives the LDO/BUCK input on the fly and forces the MAX5096/MAX5097 into LDO Mode, thereby reducing the quiescent current significantly. In Buck Mode, the MAX5096/MAX5097 operate from a 5V to 40V input voltage range and deliver up to 600mA of load current with excellent load and line regulation. The fixed-switching frequency versions of 135kHz and 330kHz are available. The MAX5096/MAX5097 DC-DC internal oscillator can be synchronized to an external clock. External compensation and a current-mode control scheme make it easy to design with. In LDO Mode, the MAX5096/MAX5097 operate from a 4V to 40V input voltage. The LDO Mode operation is intended for a lower output load current of up to 100mA. The quiescent current at 100A load in LDO Mode is only 41A (typ).