Abstract: Due to the influence of the parasitic parameters from the PCB board and components, the voltage step-up capacities of basic DC/DC converters are limited. This, which makes the basic DC/DC converters difficult to be used for some applications with a wide range of input or output voltages. Based on the Zeta converter, a single-switch high step-up coated-Zeta converter was proposed. The coat circuit does not need any active switch, which makes the driver and the control circuits of the coated-Zeta converter are identical to the basic Zeta converter. Meanwhile, compared to conventional Zeta converter, the voltage stresses on the switch devices of the coated-Zeta converter have also been decreased. Furthermore, by using PCB plane integrated inductors and gallium nitride (GaN) MOSFET, the switching frequency and power density of the coated-Zeta converter have been improved significantly. The operation principle, the performance characteristics and the design of planar integrated inductors of the coated-Zeta converter have been analyzed in detail, and a 300W experimental prototype has been built to verify the correctness of the theoretical analysis.