Single chip high efficiency step-down converter, app note from ON Semiconductors. Link here (PDF)
The LV5980MC is a fixed 370 kHz, high−output−current, Non−synchronous PWM converter that integrates a low−resistance, high−side MOSFET and a Customer Chosen, External Diode for the rectification. The LV5980MC utilizes externally compensated current mode control to provide good transient response, ease of implementation, and excellent loop stability. It regulates input voltages from 4.5 V to 23 V down to an output voltage as low as 1.235 V and is able to supply up to 3.0 A of load current. The LV5980MC includes Power Save Feature to enhance efficiency during Light Load. In low consumption mode, the device show operating current of 63 A from VIN by shutting down unnecessary circuits.