8-bit bus transceiver from the 74HC family
The SN74HC664NT: Its non-inverting, 3-state outputs let multiple devices share the bus without contention, making it a standard choice for memory-mapped I/O, peripheral interfaces, and backplane buffers in industrial control and telecom equipment. The 74HC family operates from 2 V to 6 V, so this part integrates directly into 5 V and 3.3 V mixed-voltage systems without level-shifting on the control side.
Active lifecycle — no end-of-life pressure
This removes the last-time-buy urgency that haunts older 74LS and 74ALS siblings. For RoHS-required builds, a lead-free equivalent in the 74HC family would need a different suffix — verify the package and finish before substituting.
What the 74HC family means for your bus
The 74HC series uses CMOS inputs with typical thresholds at 0.3 × VCC and 0.7 × VCC, giving wider noise margins than the bipolar 74LS family at the same supply voltage. Propagation delay and output drive are comparable to LS at 5 V, but HC draws significantly lower quiescent current — important for battery-backed or power-constrained boards. The 3-state outputs on this transceiver let you disconnect the bus when the device is not selected, avoiding bus contention in multi-drop configurations.