This part is a kind of semiconductor called P55NF06.

Function of this product has STP55NF06.

Manufacturers : ST Microelectronics

Image and pinout :

Some of the text within the PDF file :

STB55NF06, STP55NF06, STP55NF06FP N-channel 60 V, 0.015 Ω, 50 A STripFET™ II Power MOSFET in D²PAK, TO-220 and TO-220FP packages Datasheet production data Features Order code STB55NF06 STP55NF06 STP55NF06FP VDSS RDS(on) max. ID 60 V < 0.018 Ω 50 A 50 A (1) 1. Refer to soa for the max allowable current value on FP-type due to Rth value ■ 100% avalanche tested ■ Exceptional dv/dt capability Applications ■ Switching application Description These Power MOSFETs have been developed using STMicroelectronics’ unique STripFET process, which is specifically designed to minimize input capacitance and gate charge. This renders the devices suitable for use as primary switch in advanced high-efficiency isolated DCDC converters for telecom and computer applications, and appli [ ... ]

P55NF06 PDF Datasheet Download