75V Synchronous Buck Controller With Wide Input Voltage and Duty Cycle Ranges

The LM5145 75-V synchronous buck controller

regulates from a high input voltage source or from an input rail subject to high

voltage transients, minimizing the need for external surge suppression components. A

high-side switch minimum on-time of 40 ns gives large step-down ratios, enabling the

direct step-down conversion from a 48-V nominal input to low-voltage rails for

reduced system complexity and solution cost. The LM5145 continues to operate during

input voltage dips as low as 6 V, at nearly 100% duty cycle if needed, making it an

excellent choice for high-performance industrial control, robotic, datacom, and RF

power applications.

Forced-PWM (FPWM) operation eliminates switching

frequency variation to minimize EMI, while user-selectable diode emulation lowers

current consumption at light-load conditions. The adjustable switching frequency as

high as 1 MHz can be synchronized to an external clock source to eliminate beat

frequencies in noise-sensitive applications.