DocumentationDatasheet
Design Note
- DN509 - Micropower Isolated Flyback Converter with Input Voltage Range from 6V to 100V
- DN525 - Monolithic No-Opto Isolated Flyback Converter Provides Versatile Solution
Reliability Data
Product Selector Card
Press Release
- Low Power Isolated Monolithic Flyback Switching Regulator Simplifies Design & Eliminates Optocoupler
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Features
- 3V to 40V Input Voltage Range
- 0.65A, 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
- 16-Lead MSOP Package
Typical Application
Description
The LT3574 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 0.65A, 60V NPN power switch is integrated along with all control logic into a 16‑lead MSOP package.
The LT3574 operates with input supply voltages from 3V to 40V, and can deliver output power up to 3W with no external power switch. The LT3574 utilizes boundary mode operation to provide a small magnetic solution with improved load regulation.
The output voltage is easily set with two external resistors and the transformer turns ratio. Off-the-shelf transformers are available for many applications.
MS-16
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) |
Price (1k)* |
|---|---|---|---|---|---|
| LT3574EMS#PBF | MSOP | 16 | E | $3.94 | $2.76 |
| LT3574EMS#TRPBF | MSOP | 16 | E | $2.82 | |
| LT3574IMS#PBF | MSOP | 16 | I | $4.46 | $3.12 |
| LT3574IMS#TRPBF | MSOP | 16 | I | $3.18 |
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 |
|---|---|---|---|
| DC1636A | LT3574EMS Isolated Demo Board | 10V to 30VIN; VOUT = 5V @ 0.35A to 0.5A | $100.00 |