Small 3W Isolated Flyback, 30V…70Vin to 7V@430mA Reference Design


Design files


This simple isolated flyback converts 30V…70Vin to 7V@430mA. The LM5021-2 controller is suitable for green mode converters due to pulse skip mode.

  • Over 87% efficiency at full load
  • Over 70% efficiency at 10% load
  • Fast startup
  • Simple design
  • Improved light load efficiency thanks to skip mode, while working in constant switching frequency
Output voltage options PMP8657.1
Vin (Min) (V) 30
Vin (Max) (V) 70
Vout (Nom) (V) 7
Iout (Max) (A) .43
Output Power (W) 3.01
Isolated/Non-Isolated Isolated
Input Type DC
Topology Flyback- Non Sync
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A fully assembled board has been developed for testing and performance validation only, and is not available for sale.

Design files & products

Design files

Download ready-to-use system files to speed your design process.

SNVU428.PDF (569 K)

Test results for the reference design, including efficiency graphs, test prerequisites and more

SNVR442.PDF (168 K)

Detailed schematic diagram for design layout and components

SNVR443.PDF (35 K)

Complete listing of design components, reference designators, and manufacturers/part numbers

TIDC734.ZIP (22 K)

Design file that contains information on physical board layer of design PCB


Includes TI products in the design and potential alternatives.

Flyback controllers

LM502130V, 1MHZ current mode PWM controller

Data sheet: PDF | HTML

Technical documentation

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Type Title Date
Test report PMP8657 Test Results Oct. 24, 2014

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