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LM25119, LM25119-Q1

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SNVS680H – AUGUST 2010 – REVISED MAY 2016

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7 Detailed Description

7.1 Overview

The LM25119 high voltage switching regulator features all of the functions necessary to implement an efficient

dual-channel buck regulator that operates over a very wide input voltage range. The LM25119 may be configured

as two independent regulators or as a single high-current regulator with two interleaved channels. This easy-to-

use regulator integrates high-side and low-side MOSFET drivers capable of supplying peak currents of 2.5 A

(VCC = 8 V). The regulator control method is based on current mode control using an emulated current ramp.

Emulated peak current mode control provides inherent line feedforward, cycle-by-cycle current limiting and ease-

of-loop compensation. The use of an emulated control ramp reduces noise sensitivity of the pulse-width

modulation circuit, allowing reliable processing of the very small duty cycles necessary in high input voltage

applications. The switching frequency is user programmable from 50 kHz to 750 kHz. An oscillator or

synchronization pin allows the operating frequency to be set by a single resistor or synchronized to an external

clock. An undervoltage lockout and channel2 enable pin allows either both regulators to be disabled or channel2

to be disabled with full operation of channel1. Fault protection features include current limiting, thermal shutdown

and remote shutdown capability. The undervoltage lockout input enables both channels when the input voltage

reaches a user selected threshold and provides a very low quiescent shutdown current when pulled low. The

32-pin WQFN package features an exposed pad to aid in thermal dissipation.