SN74HC00 2-Input NAND Gate

SN74HC00 Pinout Configuration

Features

• Dual Input NAND Gate - Quad Package
• Typical Operating Voltage: 5V
• Operating Voltage Range: -0.5V to 7V
• DC input current: ±20mA
• Minimum logic Low voltage @+5V: 1.35V
• Minimum Logic High voltage @+5V: 3.15V
• Propagation Delay @5V : 28ns (maximum)
• Available in 14-pin PDIP, GDIP, PDSO packages

Note: Complete Technical Details can be found at the SN74HC00 datasheet given at the end of this page.

SN74HC00 Equivalents

SN54LS00, CD4011, Any two transistors can be reconfigured to form a NAND gate.

Where SN74HC00 IC is Used ?

There are many reasons of using SN74HC00 in electronic circuits. Here are a few examples where it is used.

SN74HC00 basically used for performing NAND function. The IC has four NAND gates in it, each gate can be used separately. When you want logic inverter, NAND gates in this chip can be reconfigured to make them NOT gate. So we can make SN74HC00 a four NOT gate chip if necessary.

Where high speed NAND operation is necessary. This chip has less transition times which are needed for high speed applications. So SN74HC00 can be used in high frequency systems. SN74HC00 is one of the cheapest IC. It is really popular and is available everywhere.

How to Use 74HC00 IC ?

As mentioned earlier, 74HC00 has four NAND gates. The internal connection of four gates is shown below.

Now it is good to remind you that NAND gate is combination of AND gate and NOT gate.

So NAND = AND + NOT.

The truth table of NAND gate is given as,

For understanding the NAND gate responses, let us study the internal circuitry of NAND gate.

In the example CD4011 circuit when both inputs A1 and B1 are LOW:

Both transistors Q1 and Q2 will be OFF. So the total supply voltage appears across the transistors Q1 and Q2. Because output Y1 is nothing but voltage across transistors Q1 and Q2, Y1 will be HIGH.

In the case when any one input is HIGH:

Only the relative transistor will be ON leaving the other OFF. With that the entire supply voltage appears across the transistor which is in OFF state. Because output Y1 is voltage across both transistors Q1 and Q2, Y1 will be HIGH.

When both inputs are HIGH:

Both transistors will be ON and voltage across both of them will be zero.Because output Y1 is voltage across both transistors Q1 and Q2, Y1 will be LOW.

After verifying the cases, you can tell that we have satisfied the above truth table.The output equation for NAND gate can be given as, Y=AB .

Now let us consider a simple application circuit of the chip NAND gate.

Here we have connected two inputs to two buttons and output is connected to a LED. The output logic of gate can be known by the ON and OFF states of this LED.

Under normal circumstances both buttons are not pressed and are open. With that both inputs of the gate will be LOW. When both inputs are LOW, output will be HIGH according to the truth table discussed above. Since output is HIGH the LED will turn ON.

In case one of buttons is closed. One input will be LOW and other will be HIGH. Even at this case output will be HIGH according to the truth table. Since output is HIGH the LED will turn ON.

Only when both buttons are pressed we will have LOW output turning the LED OFF.

With these three cases we have realized the truth table for chip NAND gate. We can use all four gates this way to satisfy our needs.

Applications

• Basic Logic Circuits
• Digital Circuits
• Encoders and Decoders
• Multiplexers and De-multiplexers
• Oscillator circuits
• Networking
• Networking and Digital Systems 

2D-Model (CDIP – Package)