The MAX1953 operates at a fixed 1MHz switching frequency, thus significantly reducing external component size and cost. Additionally, excellent transient response is obtained using less output capacitance. The MAX1953 operates from low 3V to 5.5V input voltage and can supply up to 10A of output current. Selectable current limit is provided to tailor to the external MOSFETs' on-resistance for optimum cost and performance. The output voltage is adjustable from 0.8V to 0.86VIN. With the MAX1954, the drain-voltage range on the highside FET is 3V to 13.2V and is independent of the supply voltage. It operates at a fixed 300kHz switching frequency and can be used to provide up to 25A of output current with high efficiency. The output voltage is adjustable from 0.8V to 0.86VHSD.