7400 Series Guide: 74HC06/74LS06

The 74×06 (ex 74LS06) is a chip with six open-collector inverters that has a maximum output voltage of 30V and a sink current of 40 mA so that they can interface with high-level circuits (such as MOSFETs), or for driving high-current loads.

When you have an open collector output, it means it’s easy to connect it to other chips that use different logic levels. However, it also means you can’t just swap it out with a regular inverter chip.

In this guide, you will learn everything you need to know about this chip and how to use inverters in your projects.

74HC06 / 74LS06 Package And Pinout
Package and pinout for 74×06

What does the 74HC06 / 74LS06 do?

The 74×06 gives you six open collector inverters that you can use individually. An inverter (or NOT gate) is a logic gate that outputs the opposite of the input. In the truth table below, you can see what the output will be for any given input:

NOT gate truth table
Truth table for the NOT gate (inverter)

How To Use This Chip

The 74LS06 comes in a 14-pin package, and you need to connect it to power before you can use it. Most 7400 ICs support a VCC voltage of 5V. One difference between the HC and LS versions of the chip is that the 74HC06 supports 2V to 6V, while the 74LS06 only supports 5V.

7400 series IC connected to 5V on a breadboard
The 74HC06/74LS06 IC connected to power

Once you’ve connected the power, you can use any of the six open-collector inverters inside.

Keep in mind that this chip has open-collector outputs which means you can only sink current, not source it.

The output of each gate can sink around 40 milliamps, which is significantly higher than normal 7400 chips. Keep in mind that this value might differ depending on the chip manufacturer.

74×06 Pinout

The 74×06 has 14 pins and contains six open-collector inverters, each with a maximum output voltage of 30V. Its pins are laid out as shown in the pinout diagram below:

74LS06 Pinout
Pin #TypeDescription
1InputInput to the first NOT gate.
2OutputOpen-collector output from the first NOT gate.
3InputInput to the second NOT gate.
4OutputOpen-collector output from the second NOT gate.
5InputInput to the third NOT gate.
6OutputOpen-collector output from the third NOT gate.
7PowerConnect to ground (GND).
8OutputOpen-collector output from the fourth NOT gate.
9InputInput to the fourth NOT gate.
10OutputOpen-collector output from the fifth NOT gate.
11InputInput to the fifth NOT gate.
12OutputOpen-collector output from the sixth NOT gate.
13InputInput to the sixth NOT gate.
14PowerPositive power supply (VCC). Connect to +5V power.
Pin overview for the 74×06 IC

Alternatives and Equivalents for 74HC06 / 74LS06

There are many versions of the 74×06 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:

  • 74HC06 (High-speed CMOS)
  • 74HCT06 (High-speed CMOS, TTL compatible)
  • 74LS06 (High-speed TTL)
  • 74LVC06 (Low Voltage TTL)
  • 74AC06 (Advanced CMOS)
  • 74ALS06 (Advanced Low-Power Schottky TTL)
  • 74F06 (Very High Speed)
  • 74C06 (CMOS, similar to the 4000-series)

Some manufacturers also add a prefix, such as the SN74HC06 and SN74LS06 by Texas Instruments.

Can’t find the 74×06 anywhere? Then try one of the following IC alternatives:

  • 74×04 – Hex inverters.
  • 74×05 – Hex inverters (with open-collector outputs).
  • 74×14 – Hex inverters (with Schmitt-trigger inputs).
  • CD4049 – Hex inverters (with high sink current).
  • CD4069 – Hex inverters
  • CD40106 – Hex inverters (with Schmitt-trigger inputs).

If you can’t find the 74×06 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.

Datasheet for the 74LS06

Download the PDF datasheet for your version of the 74×06 here:

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