Low Power Isolated Monolithic Flyback Switching Regulator Simplifies Design & Eliminates Optocoupler
- VIN Range from 3V to 40V
- Onboard 0.65A, 60V Integrated NPN Power Switch
- No Transformer, Third Winding or Opto-Isolator Required for Feedback
- Current Mode Control
- Boundary Mode Operation
- VOUT Set with Two External Resistors
- Off-the-Shelf Transformers
- Programmable Soft-Start
- Programmable Undervoltage Lockout
- Output Voltage Temperature Compensation
- Adjustable Current Limit
The LT3574LT3574 is an isolated monolithic flyback switching regulator that significantly simplifies the design of a low power isolated DC/DC converter. No opto-isolator, third winding or signal transformer is required for feedback since the output voltage is sensed from the primary-side flyback signal. The LT3574LT3574 operates over a 3V to 40V input voltage range, has a 0.65A NPN power switch and can deliver up to 3 watts of output power, making it well suited for a wide variety of industrial, medical, telecom, datacom and automotive applications.
LT3574EMS#PBFLT3574EMS#PBF Schematic
The LT3574LT3574 operates in boundary mode, which is a variable frequency current mode control switching scheme, resulting in ±5% regulation over the full line, load and temperature range. Boundary mode also permits the use of a smaller transformer compared to equivalent continuous conduction mode designs. The output voltage is easily set by two external resistors and the transformers turns ratio. Several off-the-shelf transformers identified in the data sheet can be used for numerous applications. The high level of integration and use of boundary mode operation results in a simple, clean application solution to the traditionally tough problem of isolated power delivery.
Additional features include an onboard low dropout regulator for IC power, programmable soft-start, undervoltage lockout, adjustable current limit and output voltage temperature compensation. The LT3574LT3574 is available in a small MSOP-16 package and is offered in an extended and industrial operating junctiontemperature range at -40°C to 125°C.
More info on www.linear.com/3574 or go to Design Kit Demoboard
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