Triple NOR gate for general-purpose logic
The SN74HC27D is a triple 3-input NOR gate from the 74HC family, providing three independent NOR functions in a single 14-SOIC package. It operates across a 2V to 6V supply range, making it suitable for battery-powered and 5V logic systems alike. Each of the three gates accepts three inputs and delivers a standard push-pull output capable of sourcing or sinking 5.2 mA — enough to drive a following gate input or a low-current LED indicator without a buffer.
Speed and power budget at a glance
At lower supply voltages the delay increases, so the 15 ns figure is the best-case; for 3.3 V operation expect roughly 20–25 ns. Quiescent current is just 2 µA maximum, so the gate adds negligible standing power in a mixed-signal board where the logic section is idle most of the time. Input logic thresholds track the supply: low-level is 0.5 V to 1.8 V, high-level is 1.5 V to 4.2 V (at Vcc=6 V). This means the gate interprets a 3.3 V CMOS output as a valid high without a level translator.
Supplied in a tube (bulk), this is the standard pick-and-place format for low-volume assembly or rework.
It remains a standard catalog item for new designs and replacement builds. The 74HC family is a mature, widely second-sourced logic series.