The US2JA is a 600V, 1.5A surface mount fast recovery rectifier from ON Semiconductor. It features a reverse recovery time of 75 ns and is housed in a DO-214AC (SMA) package.
US2MA is a super fast surface mount rectifier diode from onsemi, rated for 1000V repetitive peak reverse voltage and 1.5A average forward current with a 75ns reverse recovery time.