The LM5163 is an easy-to-use, ultra-low I_Q constant on-time (COT) synchronous step-down buck regulator. With integrated high-side and low-side power MOSFETs, the LM5163 is a low-cost, highly efficient buck converter that operates from a wide input voltage of 6 V to 100 V, delivering up to 0.5-A DC load current. The LM5163 is available in an 8-pin SO PowerPAD package with 1.27-mm pin pitch for adequate spacing in high-voltage applications. This constant on-time (COT) converter is ideal for low-noise, high-current, and fast load transient requirements, operating with a predictive on-time switching pulse. Over the input voltage range, input voltage feedforward is employed to achieve a quasi-fixed switching frequency. A controllable on-time as low as 50 ns permits high step-down ratios and a minimum forced off-time of 50 ns provides extremely high duty cycles, allowing V_IN to drop close to V_OUT before frequency foldback occurs. At light loads, the device transitions into an ultra-low I_Q mode to maintain high efficiency and prevent draining battery cells connected to the input when the system is in standby. The LM5163 implements a smart peak and valley current limit detection circuit to ensure robust protection during output short circuit conditions. Control loop compensation is not required for this regulator, reducing design time and external component count.

The LM5163 incorporates additional features for comprehensive system requirements, including an open-drain power good circuit for the following:

• Power-rail sequencing and fault reporting
• Internally-fixed soft start
• Monotonic start-up into prebiased loads
• Precision enable for programmable line undervoltage lockout (UVLO)
• Smart cycle-by-cycle current limit for optimal inductor sizing
• Thermal shutdown with automatic recovery

These features enable a flexible and easy-to-use platform for a wide range of applications. The LM5163 supports a wide range of end-equipment systems requiring a regulated output from a high input supply where the transient voltage deviates from the DC level. The following are examples of such end equipment systems:

• 48-V automotive systems
• High cell-count battery-pack systems
• 24-V industrial systems
• 48-V telecom and PoE voltage ranges

The pin arrangement is designed for a simple layout requiring only a few external components.