The 74hc27d chip is a 3-input three-or-not gate circuit. It is characterized by a typical 8ns delay time, working power supply voltage range 2 ~ 6v, input current < 1uA, static power supply current maximum 40uA, DC input or output voltage 0 ~ Ⅴcc, input rise or fall time 1000ns (2V), 500ns (4.5V), 400ns (6Ⅴ). The logical formula Y = (A+B+C) inverse.