16-SOIC addressable latch — 1:8 demux with 13 ns propagation
The CD74HC259MT is a 74HC-series D-Type addressable latch from Texas Instruments, configured as a 1:8 demultiplexer. It stores one of eight data bits selected by a three-bit address, with the remaining outputs held in a known high-impedance state. The 13 ns typical propagation delay keeps the latch responsive in clocked systems up to roughly 38 MHz — fast enough for most control and register-bank applications in industrial logic.
This makes the latch suitable for outdoor telecom cabinets, engine-bay control modules, and downhole instrumentation where the ambient temperature swings beyond the commercial 0°C to 70°C range. The 74HC family's CMOS logic levels are consistent across this span — no derating of the input threshold or output drive at the extremes beyond the datasheet's temperature curves. The standard output type means the latch drives rail-to-rail CMOS levels, not open-drain or three-state on the output side. For bus-oriented designs where multiple outputs share a line, a separate three-state buffer is needed — the latch itself does not tri-state its outputs.