Features and Benefits

  • Extremely Low Dropout
  • Low Cost
  • Fixed 5V Output, Trimmed to ±1%
  • 700µA Quiescent Current
  • 1mV Line Regulation
  • 5mV Load Regulation
  • Thermal Limit
  • 4A Output Current Guaranteed
  • Available in a 3-Pin TO-92 Package

Product Details

The LT1123 is a 3-pin bipolar device designed to be used in conjunction with a discrete PNP power transistor to form an inexpensive low dropout regulator. The LT1123 consists of a trimmed bandgap reference, error amplifier, and a driver circuit capable of sinking up to 125mA from the base of the external PNP pass transistor. The LT1123 is designed to provide a fixed output voltage of 5V.

The drive pin of the device can pull down to 2V at 125mA (1.4V at 10mA). This allows a resistor to be used to reduce the base drive available to the PNP and minimize the power dissipation in the LT1123. The drive current of the LT1123 is folded back as the feedback pin approaches ground to further limit the available drive current under short-circuit conditions.

Total quiescent current for the LT1123 is only 700µA. The device is available in a low cost TO-92 package.

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.


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The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

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