Features and Benefits
- High Efficiency: Up to 96%
- Very Low Quiescent Current: Only 20µA During Operation
- 300mA Output Current at VIN = 3V
- 2.5V to 5.5V Input Voltage Range
- 1.5MHz Constant Frequency Operation
- No Schottky Diode Required
- Low Dropout Operation: 100% Duty Cycle
- Stable with Ceramic Capacitors
- 0.8V Reference Allows Low Output Voltages
- Shutdown Mode Draws
- ±2% Output Voltage Accuracy
- Current Mode Operation for Excellent Line and Load Transient Response
- Overtemperature Protected
- Low Profile (1mm) ThinSOT™ Package
The LTC3405A is a high efficiency monolithic synchronous buck regulator using a constant frequency, current mode architecture. Supply current during operation is only 20µA and drops to <1µA in shutdown. The 2.5V to5.5V input voltage range makes the LTC3405A ideally suited for single Li-Ion battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems.
Switching frequency is internally set at 1.5MHz, allowing the use of small surface mount inductors and capacitors.The LTC3405A is specifically designed to work well with ceramic output capacitors, achieving very low output voltage ripple and a small PCB footprint.
The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode. Low output voltages are easily supported with the 0.8V feedback reference voltage. The LTC3405A is available in a low profile (1mm) ThinSOT package.
For fixed 1.5V and 1.8V output versions, refer to theLTC3405A-1.5/LTC3405A-1.8 data sheet.
Protected by U.S. Patents, including 6580258, 5481178.
|LTC3405A||Adj.||Stable With All Ceramic Caps|
|1.375V||Stable With All Ceramic Caps|
|LTC3405A-1.5||1.5V||Stable With All Ceramic Caps|
|LTC3405A-1.8||1.8V||Stable With All Ceramic Caps|
- Cellular Telephones
- Personal Information Appliances
- Wireless and DSL Modems
- Digital Still Cameras
- MP3 Players
- Portable Instruments
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)
DC480A-F: Demo Board for the LTC3405A 1.5MHz, 300mA Synchronous Step-Down Regulator in ThinSOT.
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:
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
To open the project file for this circuit:
Step 1: Download and install LTpowerCAD on your computer.
Step 2: Click on the link(s) in the section below to download part-specific project files.
Step 3: If the project file doesn't run, right-click the link and select "Save Target As." Then start the LTpowerCAD tool and open the project file by selecing "Open Project" from the "File" menu.
Design tools for the following parts are available in LTpowerCAD:
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.
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.