Texas Instruments' LM25017 (650 mA), LM25018 (325 mA), and LM25019 (100 mA) are 48 V synchronous step-down regulators with integrated high-side and low-side MOSFETs. The constant-on-time (COT) control scheme employed in the LM2501x requires no loop compensation, provides excellent transient response, and enables very-low step-down ratios. The on-time varies inversely with the input voltage, resulting in nearly constant frequency over the input voltage range. A high-voltage startup regulator provides bias power for internal operation of the IC and for integrated gate drivers.

A peak current-limit circuit protects against overload conditions. The undervoltage lockout (UVLO) circuit allows the input undervoltage threshold and hysteresis to be independently programmed. Other protection features include thermal shutdown and bias-supply undervoltage lockout.