At the heart of the ISL68200/01 is Renesas' proprietary R4 modulator. The R4 modulator, which stands for Rapid Robust Ripple Regulator, is based on a hysteretic current mode topology. It offers an inherently stable control loop with high control loop bandwidth. Digital adjustable loop gain is included, allowing the user to optimize transient performance over a wide range of Vin, Vout and output filter designs. One of the key features of the R4 control loop is the ability to adjust both duty cycle and switching frequency in response to load transients. On the next few slides, how this benefit translates into less output capacitance and smaller design size than competitive products will be shown. The R4 control loop also sports seamless PFM to PWM transition, meaning it can enter and exit light efficiency modes of operation in a single switching cycle.