TVS Diodes

Protect sensitive electronics from high voltage spikes with TVS diodes. These fast-acting additions efficiently right a circuit and work in a range of applications, from computing and technology to telecommunications.

If you need TVS diodes for your circuit, you can find them here at RS. We stock the best-known TVS diode manufacturers and there are different options available that are sure to help suppress voltage surges.

Read on to find out more about TVS diodes.

What are TVS diodes?

The role of a transient voltage suppressor, or TVS, diode is to protect sensitive components used in an integrated circuit from damage caused by a spike in the voltage.

As well as overvoltage, they shield against the effects of electrical arcs, which is where an electrical current jumps across a gap in a circuit, and electrical fast transients (EFT) and electro-static discharge (ESD), which are types of electrical bursts. Additionally, they protect against inductive load switching, and, in certain instances, lightning strikes.

In order to react to these voltage surges and other electrical events, the TVS diode limits the voltage at a set level. This limiting is referred to as ‘clamping'. By clamping, it suppresses the overvoltage above the breakdown voltage. The breakdown voltage is the rating that's required for the TVS diode to offer protection and conduct current away from the circuit to the ground.

The diode can conduct large currents to ground without becoming damaged. From there, it automatically resets.

When choosing a TVS diode, you'll need to consider key factors, such as the clamping voltage, circuit configuration, peak pulse current and the breakdown voltage. This helps to assess what you need for the application. For instance, you might need a 12v TVS diode or a 24v version, depending on your requirements.

Choosing a TVS diode: unidirectional vs bidirectional

As well as the factors mentioned above, you'll need to consider whether your project requires a unidirectional or bidirectional diode.

• Unidirectional device

A unidirectional device has a clamping voltage that is equal to the breakdown voltage if it is reverse-biased. There is a forward diode drop if forward-biased. It's designed to handle very large peak currents.

• Bidirectional device

A bidirectional TVS diode is best suited when dealing with signals that themselves are bidirectional. That is to say that they can experience levels of voltage that go both above and below a reference voltage, which is typically ground.

The one you choose will depend on whether you need a diode that works on both positive negative voltages or you can add one that protects against either positive or negative voltages.

TVS diode vs varistor: what's the difference?

You may have come across varistors and felt happy with the work they do in your circuit. These are devices with a resistance that varies with the voltage carried across the terminals. If there is a high transient voltage, the resistance of the varistor drops and clamps the voltage in place so that it's at a safe level.

This clamping ability makes it very similar to a TVS diode. However, there are differences between the two, so if it's a case of TVS diode vs varistor, it's worth thinking about these differences before applying them to your circuit.

First up, TVS diodes clamp at lower voltages, whereas the voltage is higher for a varistor. Next, diodes are ideal for areas where signal sensitivity is a priority. This is because they have low capacitance. Varistors, on the other hand, are effective at protecting circuits that need high capacitance.

Also, unlike varistors, TVS diodes don't degrade over time, so you can use them for as long as you need to - this difference is likely one of the main reasons why the diodes are more expensive than varistors.

Where are TVS diodes used?

TVS diodes are used in data and signal lines, MOS memory and microprocessors, along with AC/DC power lines and telecommunications equipment. They can be found in domestic electronics too.

Why buy your TVS diodes from RS?

If you are searching for TVS diodes for your circuit, you'll find that we stock a range of options from leading TVS diode manufacturers, including Littelfuse, Eaton Electronics, and General Semiconductor / Vishay. We are a leading authorized supplier of TVS diodes in North America and offer only the highest quality products.

Should you have any questions, our team can help. Get in touch and we'll help you with your queries. You can also find advice in our expert hub.