The MCD552-16io2 from Littelfuse is a Silicon Controlled Rectifier with Breakover Voltage 1600 V, Breakover Current 550 A, Gate Trigger Voltage 0.77 V, Gate Trigger Current 1372 A, Temperature Operating Range -40 to 125 Degree C. Tags: Surface Mount. More details for MCD552-16io2 can be seen below.