This ER28 high frequency switching transformer is designed for compact AC-DC step-down power conversion in adapters, chargers, smart meters and industrial control power supplies. Built on an ER28 Mn-Zn ferrite core with a vertical PCB-mount bobbin, it delivers stable output, low leakage inductance and reliable insulation under continuous operation. UL recognized materials (File No. E332338) and full OEM / ODM customization are available - windings, turns ratio, pin configuration and output voltage can all be built strictly to your drawing.

• UL Recognized Construction - manufactured with UL listed insulation materials, file number E332338, ready for global safety approval projects.
• Sandwich Winding, Low Leakage - primary/secondary interleaved winding keeps leakage inductance low and improves conversion efficiency.
• TIW / Enameled Copper Option - 100% full copper wire, triple insulated wire available for reinforced isolation designs.
• Wide Temperature Operation - stable performance from -40℃ to +130℃, suitable for outdoor smart meters and industrial cabinets.
• Vacuum Varnish Impregnated - anti-vibration, moisture proof, low audible noise.
• 100% Tested - inductance, turns ratio, Hi-pot and short-circuit test on every single piece before packing.
• Fast Custom Sampling - 5-7 working days for customized samples against your specification.

• IQC - incoming inspection on ferrite cores, bobbins, copper wire and insulation tape.
• IPQC - winding turns, tape layers and soldering checked in process.
• OQC - 100% inductance, turns ratio, DCR and Hi-pot test before shipment.
• Reliability - temperature rise test, aging test and vibration test on request.

• Inner Packing: anti-static tray / blister tray + PE bag
• Outer Packing: standard export carton, protected against moisture and impact
• Sample Lead Time: 5-7 working days
• Mass Production: 15-25 days after order confirmation
• Shipping: DHL / FedEx / UPS express, by air or by sea
• Trade Terms: EXW / FOB / CIF