LTC3547 - Dual Monolithic 300mA Synchronous Step-Down Regulator
Features
- High Efficiency Dual Step-Down Outputs: Up to 96%
- 300mA Output Current per Channel at VIN = 3V
- Automatic Low Ripple Burst Mode Operation (20mVP-P).
- Only 40µA Quiescent Current During Operation (Both Channels)
- 2.25MHz Constant-Frequency Operation
- 2.5V to 5.5V Input Voltage Range
- Low Dropout Operation: 100% Duty Cycle
- Internally Compensated for All Ceramic Capacitors
- Independent Internal Soft-Start for Each Channel
- Current Mode Operation for Excellent Line and Load Transient Response
- 0.6V Reference Allows Low Output Voltages
- Short-Circuit Protected
- Ultralow Shutdown Current: IQ < 1µA
- Low Profi le (0.75mm) 8-Lead 3mm × 2mm DFN Package
Typical Application
Description
The LTC3547 is a dual, 2.25MHz, constant-frequency, synchronous step-down DC/DC converter in a tiny 3mm × 2mm DFN package. 100% duty cycle provides low dropout operation, extending battery life in portable systems. Low output voltages are supported with the 0.6V feedback reference voltage. Each regulator can supply 300mA continuous output current.
The input voltage range is 2.5V to 5.5V, making it ideal for Li-Ion and USB powered applications. Supply current during operation is only 40µA and drops to < 1µA in shutdown. Automatic Burst Mode® operation increases efficiency at light loads, further extending battery life.
An internally set 2.25MHz switching frequency allows the use of tiny surface mount inductors and capacitors. Internal soft-start reduces inrush current during startup. All outputs are internally compensated to work with ceramic capacitors. The LTC3547 is available in a low profile (0.75mm) 3mm × 2mm DFN package.The LTC3547is also available in a fixed output voltage configuration,eliminating the need for the external feedback networks
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 |
|---|---|---|---|---|---|
| LTC3547EDDB-1#PBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
| LTC3547EDDB-1#TRMPBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
| LTC3547EDDB-1#TRPBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
| LTC3547EDDB#PBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
| LTC3547EDDB#TRMPBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
| LTC3547EDDB#TRPBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
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 | |
|---|---|---|---|---|---|---|
| LTC3547EDDB-1#PBF | 3x2 DFN-8 | E | $2.79 | Yes | ||
| LTC3547EDDB-1#TRMPBF | 3x2 DFN-8 | E | $2.79 | $2.00 | Yes | |
| LTC3547EDDB-1#TRPBF | 3x2 DFN-8 | E | $2.79 | $1.95 | Yes | |
| LTC3547EDDB#PBF | 3x2 DFN-8 | E | $2.79 | Yes | ||
| LTC3547EDDB#TRMPBF | 3x2 DFN-8 | E | $2.79 | $2.00 | Yes | |
| LTC3547EDDB#TRPBF | 3x2 DFN-8 | E | $2.79 | $1.95 | Yes | |
| Buy Now • Request Samples | ||||||
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.| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC1013A | LTC3547EDDB | Dual Monolithic Sync. Buck Converter | $100.00 | |
| Buy Now | |||
Applications
- Cellular Telephones
- Digital Still Cameras
- Wireless and DSL Modems
- PDAs/Palmtop PCs
- Portable Media Players
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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:
LTC3547
LTC3547-1
LTC3547B
LTC3547B-1
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
To open the project file for this circuit:
- Step 1: If you have not installed LTpowerCAD on this computer, download and install LTpowerCAD
- Step 2: Once LTpowerCAD is installed, click on the link(s) below to open the project file
- Step 3: If LTpowerCAD does not automatically open after clicking the link above, you can open the project file by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTpowerCAD and open the project file by selecting 'Open Project' from the 'File' menu
Design tools for the following parts are available in LTpowerCAD:
LTC3547
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
