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EFuse

Technology to reprogram computer chips

Wikipedia contributorsAdapted for Fathomly · View authors
2 min read
Source updated December 20, 2025

In computing, an eFuse (electronic fuse) is a microscopic fuse put into a computer chip. This technology was invented by IBM in 2004 to allow for the dynamic real-time reprogramming of chips. In the abstract, computer logic is generally "etched" or "hard-wired" onto a chip and cannot be changed after the chip has finished being manufactured. By utilizing a set of eFuses, a chip manufacturer can allow for the circuits on a chip to change while it is in operation.

01Mechanism of action

eFuses can be made out of silicon or metal traces. In both cases, they work (blow) by electromigration, the phenomenon where electric flow causes the conductor material to move. Although electromigration is generally undesired in chip design as it causes failures, eFuses are made of weak traces that are designed to fail before others do.

02Uses

eFuses were initially marketed by IBM as a way to provide in-chip performance tuning. If certain sub-systems fail, or are taking too long to respond, or are consuming too much power, the chip can instantly change its behavior by blowing an eFUSE. Today, most eFuses are used to etch serialization or calibration data onto a chip thus making it a read-only value.

03Descriptive term

eFuses are perhaps more commonly used as a one-time programmable ROM or write-restricted memory, and not actual physical electric fuses. This ranges from writing unique information onto CPUs, or in the case of game consoles and other restricted hardware, preventing downgrades by permanently recording a newer version. The Xbox 360, Nintendo Switch, Pixel 6 and Samsung Galaxy S22 are known for using eFuses this way.

04Implementations

eFuses used for performance adjustment or unique IDs:

eFuses known to be used for hardware restriction:

  • IBM/Microsoft Xenon CPU in the Xbox 360 game console. 768 bits of fuses.
  • Samsung Knox devices use an eFuse to detect if a non-Samsung boot path has ever been run.

05Variants

Resettable eFuses are used for protecting circuits. They act similarly to resettable fuses, and are generally shipped as a standalone chip package.

There are several ways of implementing an antifuse in silicon: see Antifuse § Antifuses in integrated circuits.

Watch videos about EFuseExplainers and documentaries on YouTube (opens in a new tab)

Sources and credits

This article is adapted from the Wikipedia article “EFuse”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

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Related topics

Antifuse

An antifuse is an electrical device that performs the opposite function to a fuse. Whereas a fuse starts with a low resistance and is designed to permanently break or open an electrically conductive path, an antifuse starts with a high resistance, an open circuit, and programming it converts it into a permanent electrically conductive path (typically when the voltage across the antifuse exceeds a certain level).

Reconfigurable computing

Reconfigurable computing is a computer architecture combining some of the flexibility of software with the high performance of hardware by processing with flexible hardware platforms like field-programmable gate arrays. The principal difference when compared to using ordinary microprocessors is the ability to add custom computational blocks using FPGAs.