Description

Designed to provide the power supply requirements of printers,

office automation, industrial, and portable equipment, the

A4490providesthreehighcurrent,highperformance,switching

regulator outputs with independent soft start.

High frequency switching allows selection of inexpensive

inductors and small ceramic output capacitors. The turn-on

cycles of the regulators are interleaved to minimize stresses on

the input capacitors and to reduce EMI. A charge pump is used

to provide the supply for driving the power switches, ensuring

operation at very wide operating duty cycles and avoiding the

need for power-draining clamp circuits.

Apower-on-reset circuit with user configurable delay indicates

when enabled regulators are in specification. The power-on-

reset flag also indicates when the input voltage drops below

specification, giving the system controller advance warning

while the switchers continue to operate down to the shutdown

level.

Internal diagnostics provide comprehensive protection against

overloads, input undervoltages, and overtemperatures.

4490-DS, Rev. 9

Features and Benefits

▪ Three buck converters

▪ 4.5 to 34 V input voltage range

▪ 550 kHz fixed frequency

▪ Multiphase switching

▪ Independent control of each converter

▪ Power-on-reset flag

▪ Internal compensation

▪ 4 × 4 mm QFN Package, small PCB footprint

Triple Output Step-Down Switching Regulator

Package: 20-contact QFN (suffix ES)

A4490

Approximate size

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Microcontroller or

Controller Logic

GND

CP1 CP2

VCP

PGND

PORZ

ENB1

ENB2

ENB3

CPOR

VDD

A4490

VBB2

LX2

FB2

VBB3

LX3

FB3

VBB1

LX1

FB1

Typical Application