1. Products
  2. Power Management
  3. LDO Linear Regulators
  4. Discrete Pass Element Linear Regulators (LDO)
  5. LT1123


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.View our quality and reliability program and certifications for more information.

Part Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
LT1123CST#PBF Material Declaration Reliability Data 3-Lead SOT-223
LT1123CST#TRPBF Material Declaration Reliability Data 3-Lead SOT-223
Wafer Fabrication Data R038 Reliability Data

Sample & Buy

Ordering FAQs

See our Ordering FAQs for answers to questions about online orders, payment options and more.


Buy Now Pricing

(**) Displayed Buy Now Price and Price Range is based on small quantity orders.


List Pricing

(*)The 1Ku 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. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


Lead Times

Please see the latest communication from our CCO regarding lead times.



Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.

Price Table Help