The 74×01 (ex 74LS01) is a basic logic chip with four open-collector NAND gates. When you’ve got an open collector output, it means you can easily connect it with other chips that use different voltage levels. But, it also means you can’t just replace it with a standard NAND gate chip.
In this how-to guide, you’ll learn all about this chip and how to use NAND gates in your own projects.
What does the 74HC01 / 74LS01 do?
The 74×01 provides you with four independent open-collector NAND gates. A NAND gate is a type of logic gate that only outputs 0 (LOW) when all of its inputs are 1 (HIGH). The truth table below illustrates the possible outputs for any particular input:
How To Use This Chip
The 74HC01 comes in a 14-pin package, and you need to connect it to power before you can use it. Most 7400 ICs can handle a supply voltage of 5V. If you want to use a different voltage, keep in mind that the HC version of the chip (74HC01) supports 2V to 6V, while the 74LS01 only supports 5V.
Once the chip has power, you can use any of the four open-collector NAND gates inside.
Note that the outputs are open collector outputs, which means you can’t use them as normal HIGH/LOW outputs.
The 74×01 has 14 pins and contains four open-collector NAND gates laid out as shown in the pinout diagram below:
|1||Output||Open-collector output from the first NAND gate.|
|2||Input||Input to the first NAND gate.|
|3||Input||Input to the first NAND gate.|
|4||Output||Open-collector output from the second NAND gate.|
|5||Input||Input to the second NAND gate.|
|6||Input||Input to the second NAND gate.|
|7||Power||Connect to ground (GND).|
|8||Input||Input to the third NAND gate.|
|9||Input||Input to the third NAND gate.|
|10||Output||Open-collector output from the third NAND gate.|
|11||Input||Input to the fourth NAND gate.|
|12||Input||Input to the fourth NAND gate.|
|13||Output||Open-collector output from the fourth NAND gate.|
|14||Power||Positive power supply (VCC). Connect to +5V power.|
Alternatives and Equivalents for 74HC01 / 74LS01
There are many versions of the 74×01 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:
- 74HC01 (High-speed CMOS)
- 74HCT01 (High-speed CMOS, TTL compatible)
- 74LS01 (High-speed TTL)
- 74LVC01 (Low Voltage TTL)
- 74AC01 (Advanced CMOS)
- 74ALS01 (Advanced Low-Power Schottky TTL)
- 74F01 (Very High Speed)
- 74C01 (CMOS, similar to the 4000-series)
Some manufacturers also add a prefix, such as the SN74HC01 and SN74LS01 by Texas Instruments.
If you can’t find the 74×01 anywhere, check out one of the following IC alternatives:
- 74HC00 – Quad 2-input open-collector NAND gates.
- 74HC03 – Quad 2-input open-collector NAND gates (with open-collector outputs).
- 74HC132 – Quad 2-input open-collector NAND gates (with Schmitt-trigger inputs).
- CD4011 – Quad 2-input open-collector NAND gates.
- CD4011 – Quad 2-input open-collector NAND gates (with Schmitt-trigger inputs).
If you can’t find the 74×01 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.