General Description
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 N-channel MOSFET and provides an adjustable current limit without external sense resistor.

FEATUREs
• Simple Voltage-mode PWM Control with Buck Rectification
• ±1% DAC Output Voltage Accuracy
• 5-Bit Digital-to-Analog Output Voltage Range from 1.05V to 1.85V
• Fast Transient Response and Excellent Output Voltage Regulation
• Fault Protection for Over-voltage and Overcurrent
• Power-good Output Voltage Monitor

APPLICATIONs
• Power Supply for VRM 8.5 Microprocessors
• Low-voltage Distributed Power Supplies
• High Power 5V to 1.05V ~ 1.85V Switching Regulator