Texas Instruments 7400 Series Part Numbering Guide

SN = Texas Instruments prefix calls out (“Standard Prefix” or “Semiconductor Network”)
SNJ = Conforms to Mil-PRF-38535 (QML)

54 = Military Grade
74 = 7400 Series of Commercial Grade Logic Integrated Circuits

Part Builder compliments of page 15 of TI Document Understanding and Interpreting Standard-Logic Data Sheets (Rev. C)