Overview
Features and Benefits
- 3A Switch in a Thermally Enhanced 16-Lead TSSOP or 8-Lead SO Package
- Constant 1.25MHz Switching Frequency
- Wide Operating Voltage Range: 3V to 25V
- High Efficiency 0.09Ω Switch
- 1.2V Feedback Reference Voltage
- Uses Low Profile Surface Mount Components
- Low Shutdown Current: 15µA
- Synchronizable to 2MHz
- Current Mode Loop Control
- Constant Maximum Switch Current Rating at All Duty Cycles*
- Available in 8-Lead SO and 16-Lead Thermally Enhanced TSSOP Packages
Product Details
The LT1765 is a 1.25MHz monolithic buck switching regulator. A high efficiency 3A, 0.09Ω switch is included on the die together with all the control circuitry required to construct a high frequency, current mode switching regulator. Current mode control provides fast transient response and excellent loop stability.
New design techniques achieve high efficiency at high switching frequencies over a wide operating voltage range. A low dropout internal regulator maintains consistent performance over a wide range of inputs from 24V systems to Li-Ion batteries. An operating supply current of 1mA improves efficiency, especially at lower output currents. Shutdown reduces quiescent current to 15µA. Maximum switch current remains constant at all duty cycles. Synchronization allows an external logic level signal to increase the internal oscillator into the range of 1.6MHz to 2MHz.
Full cycle-by-cycle current control and thermal shutdown are provided. High frequency operation allows the reduction of input and output filtering components and permits the use of chip inductors.
Applications
- DSL Modems
- Portable Computers
- Regulated Wall Adapters
- Battery-Powered Systems
- Distributed Power
Product Lifecycle
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.
Evaluation Kits (2)
Documentation
Reliability Data (1)
Evaluation Kit Manuals (2)
Tools & Simulations
LTspice
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.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.

Models for the following parts are available in LTspice:
Reference Materials
Technical Articles (6)
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.
Support & Discussions
Sample & Buy
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.