LTC3448 - 1.5MHz/2.25MHz, 600mA Synchronous Step-Down Regulator with LDO Mode
Features
- High Efficiency: Up to 96%
- Very Low Quiescent Supply Current: 32µA During Linear Regulator Operation
- 600mA Output Current (Buck Converter)
- Optionally Operates as Linear Regulator Below 3mA-External or Automatic ON/OFF
- 2.5V to 5.5V Input Voltage Range
- 1.5MHz or 2.25MHz Constant Frequency Operation or External Synchronization
- No Schottky Diode Required
- Low Dropout Operation: 100% Duty Cycle
- 0.6V Reference Allows Low Output Voltages
- Shutdown Mode Draws < 1µA Supply Current
- Current Mode Operation for Excellent Line and Load Transient Response
- Overtemperature Protected
- Low Profile (3mm × 3mm) 8-Lead DFN and 8-Lead MSOP Packages
Typical Application
Description
The LTC3448 is a high efficiency, monolithic, synchronous buck regulator using a constant frequency, current mode architecture. Supply current during operation is only 32µA (linear regulator mode) and drops to <1µA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3448 ideally suited for single Li-Ion battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems. At moderate output load levels, PWM pulse skipping mode operation provides very low output ripple voltage for noise sensitive applications.The LTC3448 automatically switches into linear regulator operation at very low load currents to maintain <5mVP-P output voltage ripple. Supply current in this mode is typically 32µA. The switch to linear regulator mode occurs at a threshold of 3mA. Linear regulator operation can be set to on, off or automatic turn on/off.
Switching frequency is selectable at either 1.5MHz or 2.25MHz, allowing the use of small surface mount inductors and capacitors.
The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode. Low output voltages are easily supported with the 0.6V feedback reference voltage. The LTC3448 is available in a low profile 3mm × 3mm DFN package or thermally enhanced 8-lead MSOP.
Protected by U.S. Patents including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131. Others pending.
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 |
|---|---|---|---|---|---|
| LTC3448EDD#PBF | 3x3 DFN-8 | DD | E | 05-08-1698 | Yes |
| LTC3448EDD#TRPBF | 3x3 DFN-8 | DD | E | 05-08-1698 | Yes |
| LTC3448EMS8E#PBF | MS-8 | MS8 | E | 05-08-1660 | Yes |
| LTC3448EMS8E#TRPBF | MS-8 | MS8 | E | 05-08-1660 | 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 | |
|---|---|---|---|---|---|---|
| LTC3448EDD#PBF | 3x3 DFN-8 | E | $2.93 | $2.05 | Yes | |
| LTC3448EDD#TRPBF | 3x3 DFN-8 | E | $2.15 | Yes | ||
| LTC3448EMS8E#PBF | MS-8 | E | $2.93 | $2.05 | Yes | |
| LTC3448EMS8E#TRPBF | MS-8 | E | $2.11 | 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 |
|---|---|---|---|
| DC840A | LTC3448EDD Demo Board | Vin=2.5V-5.5V, Vout= 1.2V/1.5V/1.8V @600mA Max | Contact Factory | |
| Buy Now | |||
Applications
- Cellular Telephones
- Personal Information Appliances
- Wireless and DSL Modems
- Digital Still Cameras
- MP3 Players
- Portable Instruments
People Who Viewed This Product Also Viewed
- LTC3542 - 500mA, 2.25MHz Synchronous Step-Down DC/DC Converter
- LT8610 - 42V, 2.5A Synchronous Step-Down Regulator with 2.5μA Quiescent Current
- LT3080 - Adjustable 1.1A Single Resistor Low Dropout Regulator
- LTC3630 - High Efficiency, 65V 500mA Synchronous Step-Down Converter
- LTC3409 - 600mA Low VIN Buck Regulator in 3mm × 3mm DFN
- LT3502/LT3502A - 1.1MHz/2.2MHz, 500mA Step-Down Regulators in 2mm × 2mm DFN and MS10
- LT3085 - Adjustable 500mA Single Resistor Low Dropout Regulator
- LT4363 - High Voltage Surge Stopper with Current Limit
- LTC3103 - 1.8μA Quiescent Current, 15V, 300mA Synchronous Step-Down DC/DC Converter
- LT3757 - Boost, Flyback, SEPIC and Inverting Controller
Product Notifications
Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.
Forgot your password? Click here.
Need help? Email mylinear@linear.com with questions and comments.
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:
LTC3448
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.
