FAQ: Logic and Voltage Translation > Logic Technology >> Current FAQ
Definition: A buffered CMOS device has output characteristics that only relies on the logical output of the gate.
In a NOR gate, different input values can result in the same output (see rows 2/3 vs 4). Having only one high signal compared to having two high signals can change the output impedance and/or current characteristics. Adding a "buffer", generally two inverters, will make the output impedance only change based on the logical output.
Refer to our application report "Understanding Buffered and Unbuffered CD4xxB Series Device Characteristics" for more in-depth information on buffered vs unbuffered devices.