This part is a kind of semiconductor called FMX12S.
Function of this product has Ultra-Fast-Recovery Rectifier Diodes.
Manufacturers : Sanken electric
Image and pinout :
Some of the text within the PDF file :
Ultra-Fast-Recovery Rectifier Diodes Absolute Maximum Ratings Parameter Type No. VRM (V) I F (AV) (A) With Heatsink IFSM (A) 50Hz Half-cycle Sinewave Single Shot Tj (°C) Tstg (°C) VF (V) max per element IR (µA) IF (A) Electrical Characteristics (Ta = 25°C) t rr t rr IR (H) (ns) (ns) (mA) IF /IRP (mA) IF /IRP (mA) Others Rth ( j-c) (°C/ W) Mass Fig. (g) VR = VRM VR=VRM, Ta=100°C max per element max per element FMX-12S FMX-22S FMX-22SL 200 5.0 10.0 15.0 35 65 100 2.5 –40 to +150 0.98 5.0 7.5 50 100 150 10.0 100/100 20.0 30.0 30 500/500 25 500/1000 100/200 4.0 2.1 A FMX-12S I FSM (A) 5 Average Forward Current I F (AV) (A) TcIF(AV) Derating D.C. VF IF Characteristics (Typical) 30 10 Forward Current IF (A) I FMS Rating 35 30 25 20 15 10 5 0 I FSM (A) 4 t [ ... ]
FMX12S PDF Datasheet Download
