LTC3561 - 1A, 4MHz, Synchronous Step-Down DC/DC Converter

Features

  • Uses Tiny Capacitors and Inductor
  • High Frequency Operation: Up to 4MHz
  • High Switch Current: 1.4A
  • Low Rds(ON) Internal Switches: 0.110Ω
  • High Efficiency: Up to 95%
  • VIN: 2.63V to 5.5V
  • 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: 240µA
  • Output Voltages from 0.8V to 5V
  • Low Noise Pulse-Skipping Operation
  • Small 8-Pin DFN Package

Typical Application

LTC3561 Typical Application
LTC3561 Typical Application

Description

The LTC3561 is a constant-frequency, synchronous, step-down DC/DC converter. Intended for medium power applications, it operates from a 2.63V 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 synchronous 0.11Ω power switches with 1.4A peak current ratings provide high efficiency. The LTC3561’s current mode architecture and external compensation allow the transient response to be optimized over a wide range of loads and output capacitors.

To further maximize battery life, the P-channel MOSFET is turned on continuously in dropout (100% duty cycle). The no-load quiescent current is only 240µA. In shutdown, the device draws <1µA.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing
RoHS
LTC3561EDD#PBF 3x3 DFN-8 DD E 05-08-1698 Yes
LTC3561EDD#TRPBF 3x3 DFN-8 DD E 05-08-1698 Yes


LTC3561 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC3561EDD#PBF 3x3 DFN-8 E $3.57 $2.50 Yes
LTC3561EDD#TRPBF 3x3 DFN-8 E $2.56 Yes
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* 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 Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Click here to view our complete list of demo boards

Applications

  • Wireless LAN Power
  • Notebook Computers
  • Digital Cameras
  • Cellular Phones
  • Board Mounted Power Supplies

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice does not automatically open after clicking the link above, 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

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice:
LTC3561
LTC3561A

LTpowerCAD

The LTpowerCAD design tool is a complete power supply design tool program that can significantly ease the tasks of power supply design. It guides users to a solution, selects power stage components, provides detailed power efficiency, shows quick loop bode plot stability and load transient analysis, and can export a final design to LTspice for simulation. Click here to download LTpowerCAD

Design tools for the following parts are available in LTpowerCAD:
LTC3561

Technical Support