2.25MHz, 600mA Synchronous Step-Down Regulator in ThinSOT
Features and Benefits
- High Efficiency: Up to 96%
- 600mA Output Current at VIN = 3V
- 2.5V to 5.5V Input Voltage Range
- 2.25MHz Constant Frequency Operation
- No Schottky Diode Required
- Low Dropout Operation: 100% Duty Cycle
- Low Quiescent Current: 350µA
- 0.6V Reference Allows Low Output Voltages
- Shutdown Mode Draws < 1µA Supply Current
- Current Mode Operation for Excellent Line and Load Transient Response
- Overtemperature Protected
- Low Profile (1mm) SOT-23 Package
The LTC3406B-2 is a high efficiency monolithic synchronous buck regulator using a constant frequency, current mode architecture. Supply current with no load is 350µA, dropping to <1µA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3406B-2 ideally suited for single Li-Ion battery-powered applications. 100% duty cycle capability provides low dropout operation, extending battery life in portable systems. PWM pulse skipping mode operation provides very low output ripple voltage for noise sensitive applications.
The switching frequency is internally set at 2.25MHz, allowing the use of tiny surface mount inductors and capacitors. The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode. Low output voltages are easily supported with the 0.6V feedback reference voltage. The LTC3406B-2 is available in a low profile (1mm) SOT-23 package. Refer to LTC3406 for applications that require Burst Mode® operation.
|LTC3406B||Adj.||1.5MHz||Burst Mode Disabled|
|LTC3406B-1.2||1.2V||1.5MHz||Burst Mode Disabled|
|LTC3406B-2||Adj.||2.25MHz||Burst Mode Disabled|
|LTC3406A||Adj.||1.5MHz||Low Ripple Burst Mode|
|LTC3406AB||Adj.||1.5MHz||Burst Mode Disabled|
|LTC3406AB-2||Adj.||2.25MHz||Burst Mode Disabled|
- 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 (1)
Demonstration circuit DC702 is a 2.25 MHz step-down converter, using the LTC3406B-2 adjustable output monolithic synchronous buck regulator. The DC702 has an input voltage range of 2.5V to 5.5V, and is capable of delivering up to 600 mA of output current at a minimum input voltage of 3V. the output voltage is set to 1.8V. The DC702 is made for noise sensitive applications, due to the LTC3406B-2 operating in pulse-skipping mode at low load currents.
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.
LTpowerCAD Project Files
Design tools for the following parts are available in LTpowerCAD:
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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.