Limited Stock

Hitachi HD74LS138P 3-to-8 Line Decoder Demultiplexer LS TTL DIP-16 Vintage – 1 Piece

ICs / Integrated Circuits • SKU RFB00518

$4.95

Genuine vintage Hitachi HD74LS138P Low-Power Schottky TTL 3-line-to-8-line decoder / demultiplexer integrated circuit in a 16-pin through-hole DIP package. THIS LISTING AND PRICE ARE FOR ONE (1) IC.

LIFECYCLE STATUS: OBSOLETE / DISCONTINUED. The exact Hitachi / Renesas HD74LS138P is officially classified as obsolete. Original Hitachi-marked DIP devices are now legacy components primarily encountered as old stock, surplus inventory, or restoration parts.

The HD74LS138P accepts three binary select inputs and decodes them into one of eight output lines. It also provides three enable inputs, allowing the device to be cascaded into larger decoding systems or used as a demultiplexer. This architecture made the LS138 especially useful for memory-address decoding, chip-select generation, data routing, computer logic, industrial control, instrumentation, communications equipment, and other digital systems.

The device operates as part of the classic 5V 74LS Low-Power Schottky TTL family. The original Hitachi specification identifies the HD74LS138P as the 16-pin DIL through-hole version.

HISTORICAL BACKGROUND:

The 74LS138 became an important building block during the expansion of microprocessor-based and TTL digital electronics. Computers and other digital systems frequently needed a method of taking a small group of address lines and selecting one memory device, peripheral, circuit section, or destination. A 3-to-8 decoder such as the LS138 could perform that function using a single IC rather than a large network of individual logic gates.

Hitachi produced its HD74LS series as a broad family of 5V bipolar general-purpose logic devices. The product family achieved extensive use over several decades in Japanese and international consumer electronics, computers, industrial equipment, instrumentation, communications hardware, and control systems.

Hitachi’s semiconductor operations later became part of the Renesas lineage, and Renesas continued to document the HD74LS138 family before ultimately classifying the HD74LS138P as obsolete. Original Hitachi-logo examples are therefore useful today when repairing vintage equipment where an era-appropriate HD74LS138P is preferred over a newly manufactured equivalent.

The photographed RF Boneyard stock carries matching Hitachi HD74LS138P markings with the additional production/lot marking OL4T. RF Boneyard preserves this marking for identification and provenance but does not assign an exact manufacturing date to the code without verified Hitachi factory documentation.