LTC3547B - Dual Monolithic 300mA Synchronous Step-Down Regulator
Features
- High Efficiency (Up to 96%) Dual Step-Down Outputs
- 300mA Output Current per Channel at VIN = 3V
- 2.25MHz Constant-Frequency Operation
- 2.5V to 5.5V Input Voltage Range
- Low Dropout Operation: 100% Duty Cycle
- No Schottky Diodes Required
- Internally Compensated for All Ceramic Capacitors
- Independent Internal Soft-Start for Each Channel
- Available in Fixed Output Versions
- 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 Profile (0.75mm) 8-Lead 3mm × 2mm DFN Package
AEC-Q100 data available for specific packages
Typical Application
Description
The LTC3547B 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 polymer and USB powered applications. Supply current is only 1µA in shutdown.
An internally set 2.25MHz switching frequency allows the use of tiny surface mount inductors and capacitors. Internal soft-start reduces inrush current during start-up. All outputs are internally compensated to work with ceramic capacitors. The LTC3547B is available in a low profile (0.75mm) 3mm × 2mm DFN package. The LTC3547B is also available in a fixed output voltage configuration selected via internal resistor dividers.
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 |
|---|---|---|---|---|---|
| LTC3547BEDDB-1#PBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
| LTC3547BEDDB-1#TRMPBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
| LTC3547BEDDB-1#TRPBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
| LTC3547BEDDB#PBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
| LTC3547BEDDB#TRMPBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
| LTC3547BEDDB#TRPBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
| LTC3547BIDDB#PBF | 3x2 DFN-8 | DDB | I | 05-08-1702 | Yes |
| LTC3547BIDDB#TRMPBF | 3x2 DFN-8 | DDB | I | 05-08-1702 | Yes |
| LTC3547BIDDB#TRPBF | 3x2 DFN-8 | DDB | I | 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 | |
|---|---|---|---|---|---|---|
| LTC3547BEDDB-1#PBF | 3x2 DFN-8 | E | $2.79 | Yes | ||
| LTC3547BEDDB-1#TRMPBF | 3x2 DFN-8 | E | $2.79 | $2.00 | Yes | |
| LTC3547BEDDB-1#TRPBF | 3x2 DFN-8 | E | $2.79 | $1.95 | Yes | |
| LTC3547BEDDB#PBF | 3x2 DFN-8 | E | $2.79 | Yes | ||
| LTC3547BEDDB#TRMPBF | 3x2 DFN-8 | E | $2.79 | $2.00 | Yes | |
| LTC3547BEDDB#TRPBF | 3x2 DFN-8 | E | $2.79 | $1.95 | Yes | |
| LTC3547BIDDB#PBF | 3x2 DFN-8 | I | $3.34 | Yes | ||
| LTC3547BIDDB#TRMPBF | 3x2 DFN-8 | I | $3.34 | $2.39 | Yes | |
| LTC3547BIDDB#TRPBF | 3x2 DFN-8 | I | $3.34 | $2.34 | 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 | |||
Designed for Automotive and Transportation Applications
AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LTC3547BIDDB#PBF | 3x2 DFN-8 | I | $3.34 | Yes | ||
| LTC3547BIDDB#TRMPBF | 3x2 DFN-8 | I | $3.34 | $2.39 | Yes | |
| LTC3547BIDDB#TRPBF | 3x2 DFN-8 | I | $3.34 | $2.34 | Yes | |
| Buy Now • Request Samples | ||||||
Applications
- Cellular Telephones
- Digital Still Cameras
- Wireless and DSL Modems
- Portable Media Players
- PDAs/Palmtop PCs
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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
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
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.
