RP519Z PWM/VFM Step-down DC/DC Converters Nisshinbo RP519Z Series 0.5A/1A PWM/VFM Step-down DC/DC Converters with Synchronous Rectifier offers synchronous rectification for improving rectification efficiency. This is achieved by replacing diodes with built-in switching transistors. Circuit performance is increased using synchronous rectification by allowing a design to reduce parts count. The current limit and thermal shutdown circuits are protection circuits for the RP519Z. High-density mounting on boards is achieved in the WLCSP−6−P8 package.