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Related Links:

Datasheets:
A8499: High-Voltage Step-Down Regulator (PDF)

Selection Guides:
Power Management ICs,

Power Management ICs: Switching Regulators

when this product is updated

Technical Publications:
A8498 and A8499: 50V-Capable Step-Down Regulators (PDF)

Press Releases:
A8499: Allegro MicroSystems, Inc. Introduces Versatile High-Voltage Step-Down Regulator,

Allegro MicroSystems, Inc. to Exhibit at Portable Design China Power Management Conference

Product Evaluation Kits:
APEK8499SLJ-01 Product Evaluation Kit

A8499
High-Voltage Step-Down Regulator

Features

• 8-50 V input range
• Integrated DMOS switch
• Flat efficiency curve across output current
• 1.5 A output in standard SOIC-8 package
• Low shutdown current
• Low cost

Applications

• Applications with 8 to 50 V input voltage range needing buck regulator for 1.5 A output current
• Consumer equipment power
• Uninterruptible power supplies (lead acid battery charger)
• Automotive: 9 to 16 V input, with higher voltage protection
• 12 V lighter-powered applications (portable DVD, etc.)
• Point of Sale (POS) applications
• Industrial applications with 24 V or 36 V bus

Description

The A8499 is a step-down regulator that will handle a wide input of operating voltage ranges. It is a fixed off-time current-mode-controlled buck regulator. The regulator requires an external clamping diode, inductor and filter capacitor. The off time is determined by an external resistor.

It will operate in both continuous and discontinuous modes. An internal blanking circuit will be used to filter out transients due to the reverse recovery of the external clamp diode. Typical blanking time is 200 nS.

The output voltage is adjustable from 1.2 V to 24 V based on a resistor divider and the 1.2 V 3 percent reference.

Reference Design and PCB Gerber Files

• A8499 Schematic (PDF)
• A8499 Gerber File (ZIP)

Schematic and gerber files are for reference only. Users should optimize the PCB layout and components for their specific application. Evaluation Board for A8499 is available upon request. Please contact your local representative.

Functional Block Diagram

Complete Part Numbers

Part Number	Package Type	RoHS Compliant	Part Composition/ RoHS Data	Temperature	Comments	Samples	Distributor Stock
A8499SLJ-T	8-lead SOT	Yes	view data	-20 °C to  85 °C	new	Due to warehouse relocation, samples will be unavailable until July 14, 2008. Contact your sales rep or purchase from distributor.
A8499SLJTR-T	8-lead SOT	Yes	view data	-20 °C to  85 °C	new	Due to warehouse relocation, samples will be unavailable until July 14, 2008. Contact your sales rep or purchase from distributor.

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.