LM5145 datasheet(14/70 Pages) TI

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8 Detailed Description

8.1 Overview

The LM5148 is a switching DC/DC controller that features all of the functions necessary to implement a high-

efficiency synchronous buck power supply operating over a wide input voltage range from 3.5 V to 80 V. The

LM5148 is configured to provide a fixed 3.3-V, 5-V, or 12-V output, or an adjustable output from 0.8 V to 55

V. This easy-to-use controller integrates high-side and low-side MOSFET gate drivers capable of sourcing and

sinking peak currents of 2.2 A and 3.2 A, respectively. Adaptive dead-time control is designed to minimize body

diode conduction during switching transitions.

Current-mode control using a shunt resistor or inductor DCR current sensing provides inherent line feedforward,

cycle-by-cycle peak current limiting, and easy loop compensation. Current-mode control using a shunt resistor

or inductor DCR current sensing also supports a wide duty cycle range for high input voltage and low-dropout

applications as well as when application require a high step-down conversion ratio (for example, 10-to-1). The

oscillator frequency is user-programmable between 100 kHz to 2.2 MHz, and the frequency can be synchronized

as high as 2.5 MHz by applying an external clock to the PFM/SYNC pin.

An external bias supply can be connected to VCCX to maximize efficiency in high input voltage applications.

A user-selectable diode emulation feature enables discontinuous conduction mode (DCM) operation to further

improve efficiency and reduce power dissipation during light-load conditions. Fault protection features include

current limiting, thermal shutdown, UVLO, and remote shutdown capability.

The LM5148 incorporates features to simplify the compliance with various EMI standards, for example CISPR 11

and CISPR 32 Class B requirements. DRSS techniques reduce the peak harmonic EMI signature.

The LM5148 is provided in a 24-pin VQFN package with an exposed pad to aid in thermal dissipation.

LM5148

SNVSC01 – FEBRUARY 2023

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LM5145 Datasheet(PDF) 14 Page - Texas Instruments