The 74×26 (ex 74LS26) is a chip that comes packed with four open-collector NAND gates. An open collector output makes it easy to interface with chips of different logic levels. But it also means you use it as a direct replacement for a standard NAND gate chip.
Learn how it works and how to use it with this beginner-friendly guide and start using open-collector NAND gates in your projects.
What does the 74LS26 do?
The 74×26 gives you four open-collector NAND gates. Each output supports a voltage of up to 15V. A NAND gate is a logic gate that outputs 0 (LOW) 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
The 74LS26 comes in a 14-pin package, and you need to connect its power pins before you can use it. Like most 7400 ICs, it supports a VCC voltage of 5V.
This chip uses open-collector outputs which means you can only sink current, not source it.
The 74LS26 can usually sink about 8 to 16 milliamps of current. But, these values might differ depending on the chip manufacturer.
74LS26 Pinout
The 74×26 has 14 pins and contains four open-collector NAND gates laid out as shown in the pinout diagram below:
Pin # | Type | Description |
---|---|---|
1 | Input | Input to the first NAND gate. |
2 | Input | Input to the first NAND gate. |
3 | Output | Open-collector output from the first NAND gate. |
4 | Input | Input to the second NAND gate. |
5 | Input | Input to the second NAND gate. |
6 | Output | Open-collector output from the second NAND gate. |
7 | Power | Connect to ground (GND). |
8 | Output | Open-collector output from the third NAND gate. |
9 | Input | Input to the third NAND gate. |
10 | Input | Input to the third NAND gate. |
11 | Output | Open-collector output from the fourth NAND gate. |
12 | Input | Input to the fourth NAND gate. |
13 | Input | Input to the fourth NAND gate. |
14 | Power | Positive power supply (VCC). Connect to +5V power. |
Alternatives and Equivalents for 74×26
There are many versions of the 74×26 chip. They all have the same functionality, but with different specifications such as supported voltages and maximum current output.
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Here’s a list of a few equivalents of this chip:
- 74HC26 (High-speed CMOS)
- 74HCT26 (High-speed CMOS, TTL compatible)
- 74LS26 (High-speed TTL)
- 74LVC26 (Low Voltage TTL)
- 74AC26 (Advanced CMOS)
- 74ALS26 (Advanced Low-Power Schottky TTL)
- 74F26 (Very High Speed)
- 74C26 (CMOS, similar to the 4000-series)
Some manufacturers also add a prefix, such as the SN74HC26 and SN74LS26 by Texas Instruments.
Can’t find the 74LS26 anywhere? Then try one of the following IC alternatives:
If you can’t find the 74LS26 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 74LS26 chip
Download the PDF datasheet for your version of the 74×26 here:
Build Something Useful This Evening
This gadget lets you use any IR remote-control to control your lamp, garden lights, heater oven, garage door, or anything else.