This part is a kind of semiconductor called 21N50C3.

Function of this product has SPB21N50C3.

Manufacturers : Infineon

Image and pinout :

Some of the text within the PDF file :

SPB21N50C3 Cool MOS™ Power Transistor Feature • New revolutionary high voltage technology • Ultra low gate charge • Periodic avalanche rated • Extreme dv/dt rated • Ultra low effective capacitances • Improved transconductance VDS @ Tjmax RDS(on) ID 560 0.19 21 PG-TO263 V Ω A Type SPB21N50C3 Package PG-TO263 Ordering Code Q67040-S4566 Marking 21N50C3 Maximum Ratings Parameter Continuous drain current TC = 25 °C TC = 100 °C Symbol SPB ID 21 13.1 ID puls EAS EAR IAR VGS VGS Ptot Tj , Tstg dv/dt 63 690 1 21 ±20 ±30 208 Value Unit A Pulsed drain current, tp limited by Tjmax Avalanche energy, single pulse ID=10A, VDD=50V A mJ Avalanche energy, repetitive tAR limited by Tjmax2) ID=21A, VDD=50V Avalanche current, repetitive tAR limited by Tjmax Gate source voltag [ ... ]

21N50C3 PDF Datasheet Download