The LTC1873 is a dual switching regulator controller optimized for high efficiency with low input voltages. It includes two complete, on-chip, independent switching regulator controllers. Each is designed to drive a pair of external N-channel MOSFETs in a voltage mode feedback, synchronous buck configuration. The LTC1873 includes digital output voltage adjustment on side 1 that conforms to the Intel Desktop VID specification. A constant-frequency, true PWM design minimizes external component size and cost and optimizes load transient performance. The synchronous buck architecture automatically shifts to discontinuous and then to Burst ModeTM operation as the output load decreases, ensuring maximum efficiency over a wide range of load currents. The LTC1873 features an onboard reference trimmed to 1% and delivers better than 1.5% regulation at the converter outputs over all combinations of line, load and temperature. Each channel can be enabled independently; with both channels disabled, the LTC1873 shuts down and supply current drops below 100A.