The ISL6401 adjustable frequency, low power, pulse width

modulating (PWM) current mode controller is designed for a

wide range of DC/DC conversion applications including

boost, flyback, and isolated output configurations. The

device is optimized to provide a high performance, low-cost

solution for Ringing SLIC (RSLIC) ring and talk power

supplies. An integrated inverter allows for easy design of

negative voltage regulation circuits with a minimal amount of

external components. Internal soft-start minimizes start-up

stress without any external components. Peak current mode

control effectively handles Ring trip transients and provides

inherent overcurrent protection.

This advanced BiCMOS design features low operating

current, adjustable operating output frequency (50kHz to

600kHz), internal soft-start and a SYNC input that allows the

oscillator to be locked to an external clock for noise sensitive

applications. DC/DC conversion efficiency is optimized by

use of a low current sense voltage. A logic level shutdown

input is included, which reduces supply current to 55μA in

the shutdown mode.

Features

? Positive and Negative Output Regulation

? Starting Supply Current . . . . . . . . . . . . . . . . . 100μA (typ.)

? Quiescent Current . . . . . . . . . . . . . . . . . . . . . . 55μA (typ.)

? Output Frequency Range. . . . . . . . . . . . 50kHz to 600kHz

? External Clock Synchronization

? Fast Transient Response with Peak Current Mode Control

? Internal Soft-Start

? Drives N-Channel MOSFET

? Logic Level Shutdown

? Leading Edge Blanking

? 1 Tolerance Voltage Reference Over Line and

Temperature

? Pb-Free Available (RoHS Compliant)

Applications

? VoIP/VoDSL Ringer and Off-Hook Voltage Generators

? Multi-Output Flyback Supplies

? Cable and DSL Modems

? Set-Top Boxes

? Wireless Local Loops

? LMDH and FTTH Supplies

? Boost Regulators

? Routers