CD4001 – an IC with four NOR Gates The CD4001 is a CMOS chip with four NOR gates. Because each gate has two inputs and it has four gates inside, it’s usually called a Quad 2-Input NOR Gate. A NOR gate combines the functionality of OR and NOT gates. It gives a HIGH output only when both inputs are LOW; otherwise, the output is LOW. Pin Overview Pin Name Pin # Type Description VDD 14 Power Supply Voltage ( 3 to 15V) GND 7 Power Ground (0V) A1 to A4 1, 5, 8, 12 Input Inputs A of the four NOR gates B1 to B4 2, 6, 9, 13 Input Inputs B of the four NOR gates Q1 to Q4 3, 4, 10, 11 Output Outputs from the four NOR gates Pin overview for the 4001 IC What is a NOR gate? A NOR gate is a logic gate that combines the functionality of both an OR and a NOT gate. It’s often called NOT-OR because it’s the same as an OR gate with a NOT gate on the output. Simply put, a NOR gate gives a HIGH output only when all the inputs are LOW as shown in the truth table below. Therefore, if you input a HIGH in any of the inputs, the result will automatically become LOW since the results of the OR gate are inverted by the NOT gate. NOR gate symbol Input A Input B Output Q 0 0 1 1 0 0 0 1 0 1 1 0 Truth Table for the NOR gate NOR gates are basic logic gates that can be used for a lot of different logical operations. You’ll often see NOR gates in the construction of flip-flops and latches. Technical Specifications Physical Case/Package DIP Mount Through Hole Number of Pins 14 Technical High Level Output Current -4.2 mA Logic Function NOR Low Level Output Current 4.2 mA Max Operating Temperature 125 °C Max Supply Voltage 15 V Min Operating Temperature -55 °C Min Supply Voltage 3 V Number of Circuits 4 Number of Elements 4 Number of Gates 4 Number of Inputs 2 Number of Outputs 1 Output Current 8.8 mA Propagation Delay 250 ns Quiescent Current 1 µA Turn-On Delay Time 250 ns
