Multi-Phase PWM Controller with PWM-VID Reference

The RT8845A is a 4/3/2/1 phase synchronous Buck PWM controller which is optimized for high performance graphic microprocessor and computer applications. The RT8845A adopts G-NAVP^TM (Green Native AVP) which is Richtek's proprietary topology derived from finite DC gain of EA amplifier with current mode control. By utilizing the G-NAVP^TM topology, the operating frequency of the RT8845A varies with VID, load and input voltage to further enhance the efficiency even in CCM. Moreover, the G-NAVP^TM with CCRCOT (Constant Current Ripple COT) technology provides superior output voltage ripple over the entire input/output range. The RT8845A provides complete fault protection functions including Over-Voltage (OV), Negative Voltage (NV), Over-Current (OC) and Under-Voltage Lockout (UVLO). The RT8845A is available in the WQFN-40L 5x5 package. The RT8845A features external reference input and PWM- VID dynamic output voltage control, in which the feedback voltage is regulated and tracks external input reference voltage. Other features include adjustable switching frequency, dynamic phase number control, internal/external soft- start, power good indicator, and enable functions.