The RT9224B is a high speed switching controller designed for use in Synchronous DC/DC buck converter for modern CPUs. The regulated output voltage is digitally programmable from 1.05V to 1.85V by a 5-bit DAC which provides initial accuracy of 1%. The RT9224B drives two external N-channel MOSFETs, providing high efficiency and eliminating the need for high cost P-channel devices. It senses the output current across the on-resistance of the Nchannel MOSFET and provides an adjustable current limit without external sense resistor.