A 53.4 KB PDF for 2N5551, carrying a Sam tag in brackets that likely names the publishing manufacturer, though the abbreviation is not spelled out.

Small 20.5 KB PDF named for 2N5551 with a UTC tag, which most likely refers to the manufacturer that published this version.

Part number 2N5551 is the sole identifier of this 74.3 KB PDF, listed as a schematic. Under the JEDEC 2N scheme the file is most plausibly a datasheet for the discrete…

Another copy of the 2N5401 datasheet, a 49.2 KB PDF whose _3 suffix probably marks an alternate version or a third saved copy rather than a documented revision.

Combined PDF of 49.6 KB whose name covers both 2N5550 and 2N5551, followed by a trailing 3 that may be an edition number but is not explained.