LTC3447 - I²C Controllable Buck Regulator in 3mm × 3mm DFN
Features
- I2C Programmable Output with 21.6mV Resolution
- Overtemperature Protected
- High Efficiency: Up to 93%
- Very Low Quiescent Current: Only 33µA
- 600mA Output Current at VIN = 3V
- 2.5V to 5.5V Input Voltage Range
- 1MHz Constant Frequency Operation
- No Schottky Diode Required
- Low Dropout Operation: 100% Duty Cycle
- Stable with Ceramic Capacitors
- Shutdown Mode Draws <1µA Supply Current
- ±2% Output Voltage Accuracy
- Standard (100kHz) or Fast Mode (400kHz) I2C
- 6-Bit Voltage DAC (0.69V to 2.05V)
- Disable Burst Mode Operation
- Enable Power Good Blanking
- Optional External Start-Up Resistors
- Soft-Start
- 10 Lead, 3mm × 3mm DFN Package
Typical Application
Description
The LTC3447 is a high efficiency monolithic synchronous current mode buck regulator. Using an I2C interface, the output voltage can be set between 0.69V and 2.05V using an internal 6-bit DAC.The buck regulator has optional external feedback resis-tors that can be used for setting the initial start up voltage. The feedback voltage reference for this start-up option is 0.6V. Once the voltage DAC is updated via the I2C, the buck regulator switches from external to internal feedback resistors. When there are no external resistors, the default start-up voltage is 1.38V.
The switching frequency is internally set at 1MHz, allowing the use of small surface mount inductors and capacitors.
In Burst Mode® operation, supply current is only 33µA, dropping to <1µA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3447 ideally suited for single cell Li-Ion battery-powered applications. 100% duty cycle capability provides low dropout operation, extending battery life in portable systems. Automatic Burst Mode operation increases efficiency at light loads, further extending battery life.
The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode.
Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131.
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 |
|---|---|---|---|---|---|
| LTC3447EDD#PBF | 3x3 DFN-10 | DD | E | 05-08-1699 | Yes |
| LTC3447EDD#TRPBF | 3x3 DFN-10 | DD | E | 05-08-1699 | 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 | |
|---|---|---|---|---|---|---|
| LTC3447EDD#PBF | 3x3 DFN-10 | E | $2.79 | $1.95 | Yes | |
| LTC3447EDD#TRPBF | 3x3 DFN-10 | E | $2.05 | 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 |
|---|---|---|---|
| DC767A | LTC3447EDD Demo Board | I2C-Controllable Buck, 2.5V ≤ VIN ≤ 5.5V, Vout = 0.7V to 2V @ 0.6A | $100.00 | |
| Buy Now | |||
Applications
- Distributed Power Supplies
- Notebook Computers
- PDAs and Other Handheld Devices
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Design Tools
Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:
- LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
- LTpowerCAD - A complete power supply selection, synthesis and design tool
- LTpowerPlay - A development environment supporting Linear Technology's Digital Power System Management (PSM) products
- PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
- Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
- LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
- And More!
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.
