LT3573 - Isolated Flyback Converter without an Opto-Coupler
Features
- 3V to 40V Input Voltage Range
- 1.25A, 60V Integrated NPN Power Switch
- Boundary Mode Operation
- No Transformer Third Winding or Opto-Isolator Required for Regulation
- Improved Primary-Side Winding Feedback Load Regulation
- VOUT Set with Two External Resistors
- BIAS Pin for Internal Bias Supply and Power NPN Driver
- Programmable Soft-Start
- Programmable Power Switch Current Limit
- Thermally Enhanced 16-Lead MSOP
AEC-Q100 data available for specific packages
Typical Application
Description
The LT®3573 is a monolithic switching regulator specifically designed for the isolated flyback topology. No third winding or opto-isolator is required for regulation. The part senses the isolated output voltage directly from the primary-side flyback waveform. A 1.25A, 60V NPN power switch is integrated along with all control logic into a 16‑lead MSOP package.
The LT3573 operates with input supply voltages from 3V to 40V, and can deliver output power up to 7W with no external power devices.The LT3573 utilizes boundary mode operation to provide a small magnetic solution with improved load regulation.
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 |
|---|---|---|---|---|---|
| LT3573EMSE#PBF | MS-16E | MSE | E | 05-08-1667 | Yes |
| LT3573EMSE#TRPBF | MS-16E | MSE | E | 05-08-1667 | Yes |
| LT3573IMSE#PBF | MS-16E | MSE | I | 05-08-1667 | Yes |
| LT3573IMSE#TRPBF | MS-16E | MSE | I | 05-08-1667 | 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 | |
|---|---|---|---|---|---|---|
| LT3573EMSE#PBF | MS-16E | E | $3.95 | $2.76 | Yes | |
| LT3573EMSE#TRPBF | MS-16E | E | $2.82 | Yes | ||
| LT3573IMSE#PBF | MS-16E | I | $4.46 | $3.12 | Yes | |
| LT3573IMSE#TRPBF | MS-16E | I | $3.18 | 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 |
|---|---|---|---|
| DC1228A | LT3573EMSE | 10V to 30VIN, 5Vout at 1A Isolated Monolithic Flyback 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 | |
|---|---|---|---|---|---|---|
| LT3573IMSE#PBF | MS-16E | I | $4.46 | $3.12 | Yes | |
| LT3573IMSE#TRPBF | MS-16E | I | $3.18 | Yes | ||
| Buy Now • Request Samples | ||||||
Applications
- Industrial, Automotive and Medical Isolated 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:
LT3573
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.
