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A4490: Triple Output Step-Down Switching Regulator (PDF)
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Power Management ICs: Switching Regulators
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A4490: Allegro MicroSystems, Inc. Announces New Triple Output Step Down Switching Regulator
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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
| Part Number | Package Type | RoHS Compliant |
Part Composition/ RoHS Data |
Temperature | Comments | Samples | Distributor Stock |
|---|---|---|---|---|---|---|---|
| A4490EESTR-T | 20-lead QFN | Yes | view data | -40 °C to 85 °C | new |
Contact Local Sales Representative or check distributor stock |
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.