What this part is and where it fits
The Texas Instruments SNJ54HC21FK is a dual 4-input positive-AND gate from the 54HC high-speed CMOS logic family. It performs the Boolean AND function on four inputs per gate, with two independent gates in one package. This is a logic gate for general-purpose combinatorial logic in systems that need a clean AND function without external inverters or multiple package counts.
Lifecycle and sourcing reality
The SNJ54HC21FK carries an active product status, meaning TI continues to manufacture and support this order code for new designs and production.
Package and handling note
The package itself is a ceramic leadless chip carrier (LCC) — the 'FK' suffix indicates a 20-terminal CQCC (ceramic quad flatpack) with J-bend leads, suitable for high-reliability and military-temperature-range applications where hermetic sealing is required.