List of 7400-series integrated circuits

Some manufacturers released some 4000-series equivalent CMOS circuits with a 74 prefix, for example, the 74HC4066[2] was a replacement for the 4066 with slightly different electrical characteristics (different power-supply voltage ratings, higher frequency capabilities, lower "on" resistances in analog switches, etc.).

Older TTL parts made by manufacturers such as Signetics, Motorola, Mullard and Siemens may have different numeric prefix and numbering series entirely, such as in the European FJ family FJH101 is an 8-input NAND gate like a 7430.

A few alphabetic characters to designate a specific logic subfamily may immediately follow the 74 or 54 in the part number, e.g., 74LS74 for low-power Schottky.

The generic descriptive feature of these alphabetic characters was diluted by various companies participating in the market at its peak and are not always consistent especially with more recent offerings.

The National Semiconductor trademarks of the words FAST[3] and FACT[4] are usually cited in the descriptions from other companies when describing their own unique designations.

Some 7416xxx parts, however, do not have a direct counterpart from the standard 74xxx range but deliver new functionality instead, which needs making use of the 7416xxx series' higher pin count.

For the following table: The widebus range in the 74xxx series includes higher-numbered parts like the 7416xxx and others, designed for extended functionality beyond standard chips.

These components often feature 16-bit or wider data handling, serving as direct expansions of existing 8-bit designs (e.g., 74373 to 7416373) or introducing entirely new capabilities.

They utilize higher pin counts to support larger data buses, advanced operations, and scalable digital logic solutions for more complex circuit requirements.

[14] The logic families available in small footprints are: AHC, AHCT, AUC, AUP, AXP, HC, HCT, LVC, VHC, NC7S, NC7ST, NC7SU, NC7SV.

Schematic of 74LS51 IC consists of a 3-3 AOI gate and 2-2 AOI gate. AOI means AND-OR-Invert (AND-NOR). Most AOI chips are currently obsolete.
74LS51 pinout diagram
TI SN74LS51 in DIP-14 package