Transformers for SMPS

Among all the inductive components we produce, the Transformer for Off-line and DC-DC Switching Converters is one of the most important.

Due to the specificity of each switching converter project, we supply these transformers as custom products only.

We mostly produce them according to a specification defined by the customer or refering to third-party specifications, like the output of automatic design tools offered by the controller’s manufacturers.

Nevertheless, automatic tools often propose design with much room for optimization.
In agreement with the customer, we can revise the specs for improved dimensions, costs or performance.
You can see here some reports proving our optimization capabilities; in these cases our components have surpassed the performance of transformers designed and optimized by electronic market leading companies.

When required, we can carry out the entire transformer design according to the customer technical data only.

Our know-how and 30+ year experience in both technical and safety standard related issues allow us to provide an excellent support, which also includes a pre-compliance analysis for the SMPS design.

If you are interested in resonant transformers, visit this page.

For flyback, push-pull, forward and any other topology, the preferential sizes of the most common transformers are listed on bottom.
These sizes are suggested but non binding, our specialty is to meet any exigence.
Bigger sizes, SMD versions, increased creepage/clearance types, etc. are also currently supplied.


  • Preferred sizes for flyback transformers and similar low power transformers.
  • Suited for converters based on any controller.
  • High dielectric strength and reinforced insulation to meet safety requirements.
Flyback transformers
Layout Power (1) Max Dimensions
E10A 0-2W 12,5 mm 16,3 mm 13,6 mm
E12A 2-6W 14,2 mm 20,6 mm 10,3 mm
E13A 4-8W 14,8 mm 19,3 mm 14,7 mm
E16A 7-15W 17,3 mm 19,3 mm 14,2 mm
E20A 15-25W 21,7 mm 25,6 mm 16,6 mm
E25A 20-45W 26,7 mm 19,4 mm 31,7 mm
E25B 40-70W 26,9 mm 33,2 mm 21,7 mm
E25C 20-45W 28,4 mm 33,7 mm 20,4 mm

(1) For reference only; Power range refers to offline flyback converters; the actual max power depends on the design details and features.
The power can be 20% or more higher in low input voltage or functional insulation flyback converters, 100% higher in push-pull converters.


The 3D file can be downloaded from the pdf sheet

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