The APW8828 is a single-phase, constant-on-time, synchronous PWM controller, which drives N-channel MOSFETs. The APW8828 steps down high voltage to generate low-voltage chipset or RAM supplies in notebook computers. The APW8828 provides excellent transient response and accurate DC voltage output in either PFM or PWM Mode. In Pulse Frequency Mode (PFM), the APW8828 provides very high efficiency over light to heavy loads with loadingmodulated switching frequencies. In PWM Mode, the converter works nearly at constant frequency for low-noise requirements. The APW8828 is equipped with accurate positive currentlimit, output under-voltage, and output over-voltage protections, perfect for NB applications. The Power-OnReset function monitors the voltage on VCC to prevent wrong operation during power-on. The APW8828 has a 1ms digital soft-start and built-in an integrated output discharge method for soft-stop. An internal integrated soft-start ramps up the output voltage with programmable slew rate to reduce the start-up current. A soft-stop function actively discharges the output capacitors with controlled reverse inductor current.