NCV891930: Low Quiescent Current 2 MHz Automotive Synchronous Buck Controller

The NCV891930 is a 2 MHz fixed−frequency low quiescent current buck controller with spread spectrum that operates up to 38 V (typical). It may be synchronized to a clock or to separate NCV891930. Peak current mode control is employed for fast transient response and tight regulation over wide input voltage and output load ranges. Feedback compensation is internal to the device, permitting design simplification. The NCV891930 is capable of converting from an automotive input voltage range of 3.5 V (4.5 V during startup) to 18 V at a constant base switching frequency above the sensitive AM band, eliminating the need for costly filters and EMI countermeasures. The switching frequency folds back to 1 MHz for input voltages between 20 V up to 38 V (typical). Under load dump conditions up to 45 V the regulator shuts down. A high voltage bias regulator with automatic switchover to an external 5 V bias supply is used for improved efficiency. Several protection features such as UVLO, current limit, short circuit protection, and thermal shutdown are provided. High switching frequency produces low output voltage ripple even when using small inductor values and an all−ceramic output filter capacitor, forming a space−efficient switching solution. (410 kHz version offered with NCV881930)