IRF520: Power MOSFET Applications


Variants of the IRF520 on the Ultra Librarian search engine.
Variants of the IRF520 on the Ultra Librarian search engine.

The IRF520 is a transistor known as a MOSFET, a transistor type developed to address the shortcomings of other transistor types. A MOSFET’s structure allows it to react to voltage changes faster than other transistors, which results in more efficient electronics. Power MOSFETs like the IRF520 are widely used in electronics manufacturing because they dissipate heat well and can switch between on and off states quickly.

What is a MOSFET?

MOSFET stands for Metal Oxide Field Effect Transistor. Compared to other transistors, MOSFETs work more quickly, handle impedance more efficiently, and have lower resistance. The main difference between a MOSFET and other transistors is that a MOSFET has a metal oxide gate electrode insulated from the main semiconductor by silicon dioxide or glass. This means that the electrode is connected to the semiconductor by a gate made of metal, laid over an oxide layer that functions as a capacitor.

A MOSFET has four terminals: drain (D), source (S), gate (G), and body (B). The body terminal is always connected to the source terminal, so MOSFETs function as three-terminal devices, though they structurally have four. The order of the terminals depends on the manufacturer, so designers should not assume the terminal order of MOSFETs.

There are two different classes of MOSFET: depletion mode and enhancement mode. Each class can have N and P variants, which are essentially identical in that current flows through them in opposite directions. Depletion mode MOSFETs have a continuous semiconductor channel between the source and drain terminals. A voltage between these terminals causes current flow, and a negative voltage induces less current than a positive voltage. Enhancement mode MOSFETS do not have a continuous channel between the terminals. A voltage across the gate and source terminals induce the current.

An Overview of the IRF520

The IRF520.
The IRF520

The IRF520 is a power MOSFET that can function at extremely high operating temperatures—up to 175 degrees Celsius. It is rated to resist multiple avalanche conditions, where the maximum voltage is exceeded and current flows unchecked through the component. This is possible because it has low resistance and dissipates heat with high efficiency.

There are multiple manufacturers for the IRF520, including Vishay, and two different variants, one which contains lead and one which does not. This means that some variants of the IRF520 contain lead solder or leaded glass in the MOSFET. Modern transistors, including the IRF520, are moving away from incorporating lead due to environmental concerns in electronics disposal, so it’s likely in the near future that newly manufactured IRF520s may not contain lead any longer.

How Can You Apply MOSFETs?

Designers rely on MOSFETs for many applications including switches in high power devices, controlling the speed of motors, and managing the activities of LEDs, high-speed switches, converters, and inverters. MOSFETs are also often used in Arduino robotics projects because of their robustness and low failure rate compared to other transistor types. In general, MOSFETs are typically used when the speed and power required for an application is too much for other transistors and the application generates a lot of heat. 

MOSFETs are especially useful in applications where on/off switching time must be low. Power MOSFETs, in particular, can be an order of magnitude faster than other transistors. Switching time refers to how long it takes for a MOSFET to turn on or off after voltage is applied or removed. Low switching times are vital to high-performance computing. They are also important when MOSFETs are situated in parallel within a circuit, since a delay in one transistor could translate its effects to those it is connected with.

MOSFETs are used in all major electronics, from mobile devices to computers. They are present inside microprocessors and CPU controllers, GPUs, and chip systems. Computer chips of all types rely on thousands of tiny MOSFETs inside of them. The applications of MOSFETs are vast, and variants of MOSFETs are ubiquitous in modern electronics. Consumers can safely assume that there are thousands of MOSFETS in every device they use.

Ultra Librarian provides the IRF520, along with many other MOSFETs, giving designers the most reliable transistors available. Working with Ultra Librarian takes the guesswork out of preparing for your next great device and puts your ideas on the road to success. Register today for free.


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