# CD4070 – An IC with Four XOR Gates

The CD4070 is a CMOS chip with four XOR gates. Because each gate has two inputs and it has four gates inside, it’s usually called a Quad 2-Input XOR Gate.

This chip is more or less identical to the CD4030.

XOR means exclusive OR, and will only give a HIGH output if one of the inputs is HIGH and the other is LOW. Or to say it in another way: The output from an XOR gate will be HIGH only if the inputs are not equal.

## What is an XOR gate?

The XOR gate outputs HIGH if its two inputs are not equal. So if one of the inputs (both not both!) is HIGH, the output will be HIGH. It’s one of the basic logic gates.

## How To Use the CD4070?

Like with all ICs in the 4000 series, you need a power supply voltage of 3 to 15V. Some versions of the chip support up to 20V. Check the datasheet of your version of the chip for exact values.

To be able to use any of the XOR gates in the chip, you need to first connect the VDD pin to the positive supply terminal and the GND pin to the negative supply terminal.

The A and B pins are the inputs to the four XOR gates in the IC.

The Q pins are the outputs from the XOR gates.

## CD4070 Example Circuit – 2 MHz clock generator

Here’s an example circuit based on the XOR gate in the 4070 IC. It uses a capacitor of 0.01µF and a resistor of 1 kΩ which should give out a frequency of about 2 MHz.

To build this you’ll need:

• CD4070BE (U1)
• 1 kΩ resistor (R1)
• 0.01µF capacitor (C1)

I came across this circuit at leap.tardate.com. And I really recommend checking out that page if you want to learn more about this circuit and how to improve it.

According to Paul who wrote the article, your chip needs to be buffered for this circuit to work. If your chip has a B after 4070, like ‘CD4070BE’, then it’s buffered. Most likely, you’ll only be able to find the buffered version these days.

## Alternatives and Equivalents for CD4070

You likely find the 4070 IC marked as CD4070, NTE4070, MC14070, HCF4070, TC4070, or HEF4070. Usually with a few extra characters at the end (Ex: CD4070BE).

This has to do with the manufacturer of the chip and the technology used. But the functionality and the pins are the same.

If they don’t have any of these chips in your local electronics store, check out my list of online stores where you can find components and tools for all your electronics projects.

Can’t find the 4070? Then try one of the following IC alternatives with 2-input XOR gates: