The 74HC21D is a high speed CMOS 4-INPUT AND GATE fabricated with silicon gate C2MOS technology. It achieves the high speed operation similar to equivalent LSTTL while maintaining the CMOS low power dissipation. The internal circuit is composed of 4 stages including buffer an output, which provide high noise immunity and stable output. All inputs are equipped with protection circuits against static discharge or transient excess voltage

High speed: tpd = 10 ns (typ.) at VCC = 5 V
Low power dissipation: ICC = 1.0 μA (max) Ta = 25 
Balanced propagation delays: tPLH ≈ tPHL
Wide operating voltage range: VCC(opr) = 2.0 to 6.0 V