The SC415 is a versatile, constant on-time, pseudo fixedfrequency, dual synchronous buck PWM controller intended for notebook computers and other battery operated portable devices. The SC415 contains all the features needed to provide cost-effective control of two independent switchmode power supplies. The two DC outputs are adjustable from 0.75V to 5.25V. Additional features for each output include cycle-bycycle current limit, voltage soft-start, under-voltage and over-voltage protection, programmable over-current protection, soft shutdown, selectable power save and non-overlapping gate drive. The SC415 provides two enable/power save inputs, two soft-start inputs, two power good outputs and an on-time adjust input. The constant on-time topology provides fast dynamic response. The excellent transient response means that SC415 based solutions require less output capacitance than competing fixed-frequency converters. Switching frequency is constant until a step in load or line voltage occurs, at which time the pulse density and frequency moves to counter the change in output voltage. After the transient event, the controller frequency returns to steady state operation. At light loads with power save enabled, the SC415 reduces switching frequency for improved efficiency.