A8499: High-Voltage Step-Down Regulator

LAST-TIME BUY: This part is in production but has been determined to be LAST TIME BUY. This classification indicates that the product is obsolete and notice has been given. Sale of this device is currently restricted to existing customer applications. The device should not be purchased for new design applications because of obsolescence in the near future. Samples are no longer available. Date of status change: December 2, 2014. Deadline for receipt of LAST TIME BUY orders: June 1, 2015.

Recommended Substitutions: For existing customer transition, and for new customers or new applications, refer to the A4447SLJTR-T.

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.

Applications include:

  • 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



Astrorep Inc. (Allegro and Sanken Semiconductors, Sanken Power Supplies)
141 John Street, Suite 300
Babylon, NY 11702
Phone: (631)422-2500
Fax: (631)422-2504
Web: www.astrorepinc.com
Email: donna.tweedy@astrorepinc.com

If this is not your local representative, find your local sales rep here.

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  • Features and BenefitsFeatures and Benefits
  • PackagingPackaging
  • Technical DocsTechnical Docs
  • NewsNews
  • 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

The A8499 is supplied in a low-profile 8-lead SOIC with exposed pad (package LJ).

LJ SOIC with exposed pad 8 pin

Reference Design and PCB Gerber Files

Allegro MicroSystems, LLC provides Gerber files for reference only. Any material, information, or instructions are provided AS IS without warranty of any kind. It is the responsibility of the User(s) to optimize any Printed Circuit Board (PCB) layout, as well as the selection of any components, for the specific application of the User(s).

Evaluation Board for A8499 is available upon request. Please contact your local representative.

Demo Board Documentation

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Product Image Functional Block Diagram

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check
Distributor Stock
A8499SLJTR-T 8-lead SOIC -20°C to 85°C Yes View Data Last time buy Contact your
local sales rep
Check Stock
APEK8499SLJ-01 DEMO BOARD -20°C to 85°C No -- Last time buy Contact your
local sales rep
Check 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.

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