The LM5165 converter is an easy-to-use synchronous buck DC-DC regulator that operates from a 3-V to
65-V supply voltage. The device is intended for step-down conversions from 3.3-V, 5-V, 12-V, 24-V, and 48-V unregulated, semi-regulated and fully-regulated supply rails. With integrated high-side and low-side power MOSFETs, the LM5165 delivers up to 150-mA DC load current with high efficiency and ultra-low input quiescent current in a very small solution size. Designed for simple implementation, a choice of operating modes offers flexibility to optimize its usage according to the target application. In constant on-time (COT) mode of operation, ideal for low-noise, high current, fast load transient requirements, the device operates with predictive on-time switching pulse. A quasi-fixed switching frequency over the input voltage range is achieved by using an input voltage feedforward to set the on-time. Alternatively, pulse frequency modulation (PFM) mode, complemented by an adjustable peak current limit, achieves exceptional light-load efficiency performance. Control loop compensation is not required with either operating mode, reducing design time and external component count.

The LM5165 incorporates other features for comprehensive system requirements, including an open-drain Power Good circuit for power-rail sequencing and fault reporting, internally-fixed or externally-adjustable soft-start, monotonic start-up into prebiased loads, precision enable with customizable hysteresis for programmable line undervoltage lockout (UVLO), adjustable cycle-by-cycle current limit for optimal inductor sizing, and thermal shutdown with automatic recovery. These features enable a flexible and easy-to-use platform for a wide range of applications. The pin arrangement is designed for simple Layout, requiring only a few external components.