4000-series integrated circuits

While initially marketed with "COS/MOS" labeling by RCA (which stood for Complementary Symmetry Metal-Oxide Semiconductor), the shorter CMOS terminology emerged as the industry preference to refer to the technology.

Speed limitations were eventually overcome with newer fabrication methods (such as self aligned gates of polysilicon instead of metal).

In the 1990s, some manufacturers (e.g. Texas Instruments) ported the 4000 series to newer HCMOS based designs to provide greater speeds.

The 4000 series facilitates simpler circuit design through relatively low power consumption, a wide range of supply voltages, and vastly increased load-driving capability (fanout) compared to TTL.

While TTL ICs are similarly modular, these usually lack the symmetrical drive strength of CMOS and may therefore require more consideration of the loads applied on its outputs.