The LTC1704/LTC1704B include a high power synchronous switching regulator controller plus a linear regulator controller. The switching regulator controller is designed to drive a pair of N-channel MOSFETs in a voltage mode, synchronous buck configuration to provide the main supply. The constant frequency, true PWM architecture switches at 550kHz, minimizing external component size, cost and optimizing load transient performance. The LTC1704 features automatic transition to power saving Burst Mode operation at light loads. The LTC1704B does not shift into Burst Mode operation at light loads, eliminating low frequency output ripple at the expense of light load efficiency. The linear regulator controller is designed to drive an external NPN power transistor to provide up to 2A of current to an auxiliary load.