1. Products
  2. Power Management
  3. Switching Regulators
  4. Step-Down (Buck) Regulators
  5. Internal Power Switch Buck Regulators
  6. LTC1149


Features and Benefits

  • Operation to 48V Input Voltage
  • Ultrahigh Efficiency: Up to 95%
  • Current Mode Operation for Excellent Line and Load Transient Response
  • High Efficiency Maintained over Wide Current Range
  • Logic-Controlled Micropower Shutdown
  • Short-Circuit Protection
  • Very Low Dropout Operation: 100% Duty Cycle
  • Synchronous FET Switching for High Efficiency
  • Adaptive Nonoverlap Gate Drives
  • Available in 16-Pin Narrow SO Package

Product Details

The LTC1149 series is a family of synchronous step down switching regulator controllers featuring automatic Burst Mode operation to maintain high efficiencies at low output currents. These devices drive external complementary power MOSFETs at switching frequencies up to 250kHz using a constant off-time current-mode architecture.

Special onboard regulation and level-shift circuitry allow operation at input voltages from dropout to 48V (60V absolute max). The constant off-time architecture maintains constant ripple current in the inductor, easing the design of wide input range converters. Current mode operation provides excellent line and load transient response. The operating current level is user-programmable via an external current sense resistor.

The LTC1149 series incorporates automatic power saving Burst Modeoperation when load currents drop below the level required for continuous operation. Standby power is reduced to only about 8mW at VIN = 12V. In shutdown, both MOSFETs are turned off.


  • Notebook and Palmtop Computers
  • Portable Instruments
  • Battery-Operated Digital Devices
  • Industrial Power Distribution
  • Avionics Systems
  • Telecom Power Supplies

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.

Tools & Simulations


LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.


Models for the following parts are available in LTspice:


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
LTC1149CN#PBF Material Declaration Reliability Data 16-Lead PDIP (Narrow 0.30 Inch)
LTC1149CN-3.3#PBF Material Declaration Reliability Data 16-Lead PDIP (Narrow 0.30 Inch)
LTC1149CN-5#PBF Material Declaration Reliability Data 16-Lead PDIP (Narrow 0.30 Inch)
LTC1149CS#PBF Material Declaration Reliability Data 16-Lead SOIC (Narrow 0.15 Inch)
LTC1149CS#TRPBF Material Declaration Reliability Data 16-Lead SOIC (Narrow 0.15 Inch)
LTC1149CS-3.3#PBF Material Declaration Reliability Data 16-Lead SOIC (Narrow 0.15 Inch)
LTC1149CS-3.3#TRPBF Material Declaration Reliability Data 16-Lead SOIC (Narrow 0.15 Inch)
LTC1149CS-5#PBF Material Declaration Reliability Data 16-Lead SOIC (Narrow 0.15 Inch)
LTC1149CS-5#TRPBF Material Declaration Reliability Data 16-Lead SOIC (Narrow 0.15 Inch)
Wafer Fabrication Data R245 Reliability Data

PCN-PDN Information

Select a model from the dropdown below to subscribe to PCN/PDN notifications and view past notifications as well.

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.



A Sample link will be shown above, next to the part, only for parts that are included in our sample program. Selecting the Sample button 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