74266 Quad 2-Input Exclusive-NOR Gates

74266 Quad 2-Input Exclusive-NOR Gates

The 74×266 is a chip with four open-collector XNOR gates. This type of output makes it simple to connect it to other chips that use different logic levels. But it also means you can’t use this chip as a direct replacement for a normal XNOR gate chip.

In this guide, you will learn all about this chip and how you can use its XNOR gates in your own circuit.

What does the 74LS266 do?

The 74×266 gives you four open-collector XNOR gates that can be used individually. An XNOR gate is a logic gate that outputs 1 (HIGH) if its inputs are equal (both 1 or both 0). In the truth table below, you can see what the output will be for any given input:

How To Use This Chip

The 74Ls266 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 74HC266 supports 2V to 6V, while the 74LS266 only supports 5V.

Once it’s connected, you can use any of the four open-collector XNOR gates inside.

This chip uses open-collector outputs. That means you can only sink current (current can flow into the chip), not source it (current cannot flow out of the chip).

Each gate output of the 74HC266 can sink about 4 mA when powered with 5V. While the 74LS266 can usually sink about 8 mA of current. These values can vary between manufacturers of the chip though.

74×266 Pinout

The 74×266 has 14 pins and contains four open-collector XNOR gates laid out as shown in the pinout diagram below. Each gate has the open-collector symbol, to remind you of the type of output:

Technical Specifications

74266 Datasheet