7400 Series Guide: 74HC08/74LS08 (AND gates)

This IC, often found as 74LS08 or 74HC08, is a chip with four basic AND gates. The AND gate is a logic gate – one of the most basic building blocks in digital electronics. The chip comes in a 14-pin package with the following pinout:

In this guide, you will learn what the 74×08 IC does and how to hook it up in a circuit.

What does the 74C08 / 74LS08 do?

The 74×08 gives you four basic AND gates that can be used individually. An AND gate is a logic gate that outputs 1 (HIGH) only if all of its inputs are 1 (HIGH). In the truth table below, you can see what the output will be for any given input:

How To Use This Chip

Like every other chip in the 7400 series, this IC needs to be connected to power before you can use it. Most 7400 ICs support a VCC voltage of 5V. One difference between the HC and LS version of the chip is that the 74HC08 supports 2V to 6V, while the 74LS08 supports only 5V.

Once it’s connected, you can use any of the four basic AND gates inside.

The amount of current you can pull out of each AND gate depends on which chip you are using.

74HC08:
Each output can sink or source 4 mA when powered with 5V.

74LS08:
HIGH-Level Output Current: 0.4 mA
LOW-Level Output Current: 8 mA

74×08 Pinout

The 74×08 has 14 pins and contains four basic AND gates laid out as shown in the pinout diagram below:

Pin Name	Pin #	Type	Description
1A	1	Input	Input to the first AND gate.
1B	2	Input	Input to the first AND gate.
1Y	3	Output	Output from the first AND gate.
2A	4	Input	Input to the second AND gate.
2B	5	Input	Input to the second AND gate.
2Y	6	Output	Output from the second AND gate.
GND	7	Power	Connect to ground.
3Y	8	Output	Output from the third AND gate.
3A	9	Input	Input to the third AND gate.
3B	10	Input	Input to the third AND gate.
4Y	11	Output	Output from the fourth AND gate.
4A	12	Input	Input to the fourth AND gate.
4B	13	Input	Input to the fourth AND gate.
VCC	14	Power	Positive power supply. Connect to +5V power.

74×08 Circuit Example

Here’s a simple project you can build using one AND gate from the 74×08 IC.

The pull-down resistors pull both inputs to the AND gate LOW when the buttons are not pushed. Push any of the buttons, and you’ll make the input pin HIGH. A HIGH on both inputs will turn on the output and thereby turn on the Light-Emitting Diode (LED).

The LED will only turn on if you push both buttons at the same time.

To build this circuit, you’ll need the following parts:

• 1 x 74HC08
• 1 x Light-Emitting Diode (LED)
• 2 x 10 kΩ resistor (R1-R2)
• 1 x 1 kΩ resistor (R3)
• 2 x pushbutton

Alternatives and Equivalents for 74HC08 / 74LS08

There are many versions of the 74×08 chip. They all have the same functionality, but with different specifications such as supported voltages and maximum current output.

Here’s a list of a few equivalents of this chip:

• 74HC08 (High-speed CMOS)
• 74HCT08 (High-speed CMOS, TTL compatible)
• 74LS08 (High-speed TTL)
• 74LVC08 (Low Voltage TTL)
• 74AC08 (Advanced CMOS)
• 74ALS08 (Advanced Low-Power Schottky TTL)
• 74F08 (Very High Speed)
• 74C08 (CMOS, similar to the 4000-series)

Some manufacturers also add a prefix, such as the SN74HC08 and SN74LS08 by Texas Instruments.

If you can’t find the 74×08 IC in your local electronics store, don’t worry, you’ll most likely find it in one of the stores listed on this page of online stores where you’ll find components and tools for all your electronics projects. If not, check out one of these alternatives:

• 74×09 – Quad 2-input AND gates (with open-collector outputs).
• 74×7001 – Quad 2-input AND gates (with Schmitt-trigger inputs).
• CD4081 – Quad 2-input AND gates.

Datasheet for the 74LS08 and 74HC08 chips

Download the PDF datasheet for your version of the 74×08 here:

• SN74HC08 (Texas Instruments)
• SN74LS08 (Texas Instruments)
• 74HC08 (Futurlec)
• 74LS08 (Futurlec)
• 74HC08 (Diodes Inc)