78253J MAX253-Compatible Converter Transformers Murata Power Solutions 78253J MAX253-Compatible Converter Transformers are specifically designed for use with the Maxim MAX253 chipset to provide isolated power supplies. These transformers feature J-STD-020D reflow, toroidal construction, and isolation to 4kVDC. These devices are available in 3.3V and 5V versions. Murata Power Solutions has provided a center-tapped secondary winding, which allows for full-bridge, half-bridge, or voltage doubling.