XNOR with open-drain output — where it fits in the 74HCS family
The SN74HCS266PWR is a quad 2-input XNOR (Exclusive NOR) gate from the 74HCS series, combining Schmitt-trigger inputs with open-drain outputs. The open-drain output means the gate can only pull the output low; a pull-up resistor to the desired logic voltage sets the high level, which allows wired-AND connections or level translation to a higher-voltage bus without an external translator. Each of the four independent gates accepts two inputs. The Schmitt-trigger hysteresis cleans up slow or noisy edges — a 1V to 3V low-level threshold versus a 1.5V to 4.2V high-level threshold gives about 0.5V of typical hysteresis across the 2V to 6V supply range.
Supply range, temperature grade, and quiescent draw
Rated for 2V to 6V supply, the part covers 3.3V and 5V logic rails without a separate regulator. The -40°C to 125°C operating range spans industrial and automotive ambient — the 125°C ceiling covers under-hood and engine-bay environments where standard 85°C logic would derate. Quiescent current maxes at 2 µA across the full voltage and temperature range. For a battery-powered sensor node that spends most of its life in standby, the gate's own draw is negligible — the pull-up resistor on the open-drain output will dominate the idle current budget. Propagation delay is 16 ns typical at 6V with a 50 pF load. The open-drain output's rise time is set by the external pull-up resistor and load capacitance, not by the gate itself — a 1 kΩ pull-up into 50 pF adds about 55 ns of RC rise, which sets the practical data rate ceiling more than the 16 ns propagation delay.
Package and sourcing posture
Housed in a 14-TSSOP package (4.40 mm body width, 0.65 mm pin pitch), the SN74HCS266PWR is a surface-mount part suited for dense PCB layouts. The Tape & Reel (TR) and Cut Tape (CT) packaging options support both production reels and prototype quantities. Texas Instruments lists the product status as Active. Sourced through franchised and independent distribution channels; availability and current pricing confirmed at RFQ against the BOM line.