The 4000 series of integrated circuits got its start in 1968 at RCA. They implement a variety of logic functions using CMOS (Complementary Metal–Oxide–Semiconductor) technology. Used as a alternative to the 7400 series of TTL logic circuits they have the advantage of lower power consumption, wider supply voltage range(3-15v) and increased fanout. Their high impedance makes them more susceptible to electrostatic fields than their bipolar TTL cousins.