A4490: Triple Output Step-Down Switching Regulator

Description

Designed to provide the power supply requirements of printers, office automation, industrial, and portable equipment, the A4490 provides three high current, high performance, 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.

A power-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. The A4490 is provided in a 20-contact, 4 mm × 4 mm, 0.75 mm nominal overall height QFN, with exposed pad for enhanced thermal dissipation. It is lead (Pb) free, with 100% matte tin leadframe plating.

Applications

  • Photo, inkjet, and portable printers
  • Industrial
  • Hand-held devices
  • Portable applications

Top Features

  • Three buck converters in a single IC
  • Saves significant PCB space and component count vs single regulators
  • 4.5 to 34 V input voltage range
  • 550 kHz fixed frequency – stable with ceramic output capacitors
  • Multiphase switching reduces EMI and input supply stress
  • Independent control of each converter simplifies power sequencing
  • Power-on-reset flag with adjustable delay
  • Internal compensation
  • 4 × 4 mm QFN Package, small PCB footprint

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Compliant
Part Composition /
RoHS Data
Comments Samples Check Stock
A4490EESTR-T 20-lead QFN -40°C to 85°C Yes View Data Contact your
local sales rep
Check
Distributor Stock
APEK4490EES-01-T DEMO BOARD -40°C to 85°C No -- Contact your
local sales rep
Check
Distributor Stock

Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm.

Packaging

The A4490 is provided in a 20-contact, 4 mm × 4 mm, 0.75 mm nominal overall height QFN, with exposed pad for enhanced thermal dissipation (suffix ES). It is lead (Pb) free, with 100% matte tin leadframe plating.

ES QFN 20-lead