We present a design strategy for a buck converter, which fulfills the high dynamic requirements of efficient envelope amplifier needed by modern efficiency enhancement techniques for power amplifiers. The proposed DC–DC converter has an innovative control system, which makes it fast, robust, and resource saving. A mathematical model describes its dynamic behavior and is used to find a setup, which gives an optimal compromise between the dynamic performance and efficiency. The approach is applicable to various state-of-the-art communication standards. As an example, an envelope following (EF) power amplifier (PA) for the wideband code-division-multiple-access (W-CDMA) modulation scheme is treated. The corresponding buck converter is implemented in a monolithic chip (except the inductor and the capacitor of the output filter). The measurements with an industry standard W-CDMA PA (RMPA2265) match very well with the forecast of the model and confirm doubling of the average efficiency.