Features and Benefits
- Uses Tiny Capacitors and Inductor
- High Frequency Operation: Up to 4MHz
- Low RDS(ON) Internal Switches: 0.110Ω
- High Efficiency: Up to 96%
- Stable with Ceramic Capacitors
- Current Mode Operation for Excellent Line and Load Transient Response
- Short-Circuit Protected
- Low Dropout Operation: 100% Duty Cycle
- Low Shutdown Current: IQ ≤ 1μA
- Low Quiescent Current: 60μA
- Output Voltages from 0.8V to 5V
- Selectable Burst Mode® Operation
- Sychronizable to External Clock
- Small 3mm × 3mm, 10-Lead DFN Package
The LTC3568 is a constant frequency, synchronous step- down DC/DC converter. Intended for medium power applications, it operates from a 2.5V to 5.5V input voltage range and has a user configurable operating frequency up to 4MHz, allowing the use of tiny, low cost capacitors and inductors 2mm or less in height. The output voltage is adjustable from 0.8V to 5V. Internal sychronous 0.11Ω power switches with 2.4A peak current ratings provide high efficiency. The LTC3568’s current mode architecture and external compensation allow the transient response to be optimized over a wide range of loads and output capacitors.
The LTC3568 can be configured for automatic power saving Burst Mode operation to reduce gate charge losses when the load current drops below the level required for continuous operation. For reduced noise and RF interference, the SYNC/MODE pin can be configured to skip pulses or provide forced continuous operation.
To further maximize battery life, the P-channel MOSFET is turned on continuously in dropout (100% duty cycle) with a low quiescent current of 60μA. In shutdown, the device draws <1μA.
- Notebook Computers
- Digital Cameras
- Cellular Phones
- Handheld Instruments
- Board Mounted Power Supplies
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 1206 is a step-down converter, using the LTC3568 monolithic synchronous buck regulator. The DC1206 has an input voltage range of 2.25V to 5.5V, and is capable of delivering up to 1.8A of output current at a minimum input voltage of 2.25V. The output voltage of the DC1206 can be set as low as 0.8V, the reference voltage of the LTC3568. At low load currents, the DC1206 can operate in either noise sensitive applications, due to the capability of the LTC3568 to operate in pulse-skipping mode, or in high efficiency applications, because the LTC3568 can also operate in Burst-Mode®. During Burst-Mode® operation, the output ripple voltage is still low – less than 30 mV – due to the improvements made in the design of the LTC3568.
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.
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:
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:
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.