Open-drain hex inverter for mixed-voltage bus interfaces
The SN74HC05PWR is a 74HC-series hex inverter with open-drain outputs — each of the six inverters can sink 5.2 mA low but cannot source current high, which makes this part the natural choice for wired-OR buses, level translation to a higher pull-up voltage, or driving LEDs and relay coils where the load connects to a supply rail above the logic supply.
Propagation delay and output drive — timing closure check
Maximum propagation delay is 20 ns at 6 V with a 50 pF load — this sets the data-rate ceiling for the bus; at 3.3 V the delay is typically longer, so budget the worst-case 20 ns into the timing analysis for a multi-drop open-drain line running at 10-20 MHz. Quiescent current is 2 µA max, which matters for battery-backed or always-on sections where the inverter sits idle between transactions. The input logic levels are 0.5 V to 1.8 V low and 1.5 V to 4.2 V high across the supply range — the wide low threshold means a 3.3 V signal driving a 5 V-powered inverter still registers a valid low without a level shifter ahead of the input.
ROHS3 compliant — no restricted substances above the threshold; the part ships with standard TI compliance documentation (RoHS, REACH) on request.