Tri-State Buffer 101

Tri-State Buffers are a common form of logic for many bus applications. The tri-state obviously stands for three states, which represent the 3 possible out put states: high, low and floating.

• High is logic 1
• Low is logic 0
• Floating is not controlled by the buffer (Z)

During the floating state the Output is not being controlled in anyway by the input signal.

There are two inputs and one output.

• Input Signal - is the logic level that is forwarded to the Output signal
• Input Control Signal - determines if the Output Signal is equal to the Input Signal or if the Output Signal is floating

• If the Input Control Signal is logic level High (1) the Output Signal is equal to the Input Signal
• If the Input Control Signal is logic level Low (0) the Output Signal is in a floating state