The CD74HCT138E is a 74HCT-series 3-to-8 line decoder/demultiplexer. It takes a 3-bit binary input and selects one of eight active-low outputs. The 16-pin DIP package (0.300" body) is a through-hole legacy footprint still common in repair depots, breadboard prototyping, and low-volume industrial controllers that avoid SMT rework.
This is a mature, stable line.
Package and handling note
Supplied in a 16-pin PDIP, shipped in tubes. Through-hole means no bake before reflow — just standard ESD handling. The 0.300" row spacing fits common prototype boards and sockets. No MSL rating applies to DIP packages; they are inherently moisture-resistant.