The SC1159 is a synchronous-buck switch-mode controller designed for use in single ended power supply applications where efficiency is the primary concern. The controller is a hysteretic type, with a user selectable hysteresis. The SC1159 is ideal for implementing DC/DC converters needed to power advanced microprocessors such as Pentium llI and Athlon, in both single and multiple processor configurations. Inhibit, under-voltage lockout and soft-start functions are included for controlled power-up.