The Micrel MIC2174/MIC2174C is a fixed-frequency, synchronous buck controller featuring adaptive on-time control. The MIC2174/MIC2174C operates over an input supply range of 3V to 40V at a fixed switching frequency of 300kHz and is capable of driving 25A of output current. The output voltage is adjustable down to 0.8V. A unique Hyper Speed ControlTM architecture allows for ultra-fast transient response while reducing the output capacitance. It also makes ultra-fast transient response while reducing the output capacitance and also allows for extremely low duty-cycle operation. The MIC2174 / MIC2174C utilizes an adaptive TON ripple controlled architecture. A UVLO is provided to ensure proper operation under power-sag conditions to prevent the external power MOSFET from overheating. A soft-start is provided to reduce inrush current. Foldback current limit and "hiccup" mode short-circuit protection ensure FET and load protection.