LM5145 datasheet(14/60 Pages) TI2

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6 Detailed Description

6.1 Overview

The LM25139 is a switching 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 4V to 42V. The LM25139 is

configured to provide a fixed 3.3V, 5V, or an adjustable output between 0.8V to 36V. This easy-to-use controller

integrates high-side and low-side MOSFET gate drivers capable of sourcing and sinking peak currents of 1.65A

and 2.4A, respectively. Adaptive dead-time control is designed to minimize body diode conduction.

Peak 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 also

supports a wide duty cycle range for high input voltage and low-dropout applications as well as when an

application require a high step-down conversion ratio (for example, 10-to-1). The oscillator frequency is user-

programmable between 100kHz to 3.2MHz, and the frequency can be synchronized as high as 3.2MHz

by applying an external clock to FPWM/SYNC. A user-selectable PFM mode feature enables discontinuous

conduction mode (DCM) operation to further improve efficiency and reduce power dissipation during light-load

conditions.

The LM25139 incorporates features to simplify the compliance with various EMI standards, such as CISPR 11

for industrial applications. DRSS techniques reduce the peak harmonic EMI signature. The LM25139 is provided

in a 16-pin RGT package with an exposed pad to aid in thermal dissipation.

LM25139

SLVSJ80 – OCTOBER 2025

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LM5145 Datasheet(PDF) 14 Page - Texas Instruments