You can tie them either way -- the key is not to let any CMOS inputs float, since they can float to mid-rail, which draws excessive current in the input stage, and can make the output oscillate creating noise. Whether the (open) output pin is high or low doesn't affect the Idd current draw for the CMOS gate.TheRedDevil18 said:I have a quad 2 input NOR gate ic in which I am only using two of the four gates. I have read on the internet that unused inputs must be tied to ground. But if I tie these inputs to ground then I would get a one on the output. Will that draw excessive current ?, should I tie them to Vcc instead so my output is zero ?
An IC unused input NOR gate is a type of logic gate that has multiple input pins and one output pin. It follows the NOR logic, where the output is only low when all of the input pins are high. Unused inputs refer to the input pins that are not connected to any external circuit.
An IC unused input NOR gate works by using transistors to compare the voltage levels of the input pins. If all of the input pins are high, the output will be low. However, if any of the input pins are low, the output will be high.
The purpose of unused inputs in an IC unused input NOR gate is to provide flexibility in circuit design. These inputs can be left unconnected, used as a control input, or connected to a fixed voltage level to create different logic functions.
In most cases, unused inputs in an IC unused input NOR gate will not affect the output. However, if the unused inputs are not connected to a fixed voltage level, they may cause unpredictable behavior and affect the output.
Unused inputs in an IC unused input NOR gate can be utilized by connecting them to a fixed voltage level to create different logic functions, such as an inverter or a buffer. They can also be used as control inputs for more complex logic circuits.