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Related Links:

Datasheets:
A4490: Triple Output Step-Down Switching Regulator (PDF)

Selection Guides:
Power Management ICs,

Power Management ICs: Switching Regulators

when this product is updated

Press Releases:
A4490: Allegro MicroSystems, Inc. Announces New Triple Output Step Down Switching Regulator

A4490
Triple Output Step-Down Switching Regulator

Features and Benefits

• Three buck converters
• 4.5 to 34 V input voltage range
• 0.8 to 5 V output 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

Applications

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

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.

Functional Block Diagram

Complete Part Numbers

Part Number	Package Type	RoHS Compliant	Part Composition/ RoHS Data	Temperature	Comments	Samples	Distributor Stock
A4490EES-T	20-lead QFN	Yes	view data	-40 °C to  85 °C	new	Contact Local Sales Representative
A4490EESTR-T	20-lead QFN	Yes	view data	-40 °C to  85 °C	new	samples not available

Allegro's products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the failure of that life support device or system, or to affect the safety or effectiveness of that device or system.