The LM5169 and LM5168 synchronous buck converters are designed to regulate over a wide input voltage range, minimizing the need for external surge suppression components. A minimum controllable on time of 50 ns facilitates large step-down conversion ratios, enabling the direct step-down from a 48-V nominal input to low-voltage rails for reduced system complexity and design cost. The LM516x operates during input voltage dips as low as 6 V, at nearly 100% duty cycle if needed, making the device an excellent choice for wide input supply range industrial and high cell count battery pack applications. With integrated high-side and low-side power MOSFETs, the LM5169 delivers up to 0.65-A of output current and the LM5168 delivers up to 0.3-A of output current. A constant on-time (COT) control architecture provides nearly constant switching frequency with excellent load and line transient response. The LM516x is available in FPWM or auto mode versions. FPWM mode provides forced CCM operation across the entire load range supporting isolated fly-buck converter applications. Auto mode enables ultra-low I_Q and diode emulation mode operation for high light-load efficiency.