ON Semiconductor NCP81246 Three-Rail Controller offers an optimized 3-rail multi-phase buck solution for Intel IMVP8 compatible CPUs. The NCP81246 includes a two-phase controller and two one-phase controllers. Two-phase ControllerThe two-phase controller provides differential-inductor DCR current sensing, true differential voltage sensing, input voltage feed-forward, and adaptive voltage positioning to accurately regulate power for the IMVP8 Rail2. One-phase ControllersDesigners can use the two 1-phase controllers for the Rail1, Rail3 and, Rail4 rails. The two single-phase controllers support Core, GT, and SA rails in the 2-1-1, 1-2-1, and 1-1-1 configurations. The single-phase rails include a programmable ultra-low offset current monitor amplifier to deliver ultra-high accuracy current monitoring. RPM Operation The two-phase and one-phase controllers use ON Semiconductors patented high-performance RPM operation. The RPM operation maximizes transient response while ensuring for smooth transitions between discontinuous frequency scaling operation and continuous mode full-power operation.