EFuse

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Technology to reprogram computer chips

title: "EFuse" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["ibm-computer-hardware"] description: "Technology to reprogram computer chips" topic_path: "general/ibm-computer-hardware" source: "https://en.wikipedia.org/wiki/EFuse" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Technology to reprogram computer chips ::

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.

Mechanism 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.

One-time Programmable Fuse (Intact) (52431548708).jpg|Intact fuse One-time Programmable Fuse (Blown) (52431538243).jpg|Blown fuse

Uses

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.

Descriptive 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.

Implementations

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. 768bits of fuses.
  • Samsung Knox devices use an eFuse to detect if a non-Samsung boot path has ever been run.

Variants

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 .

References

References

  1. "IBM's eFuse technology portends adaptable chips".
  2. DCC. (1989-03-14). "Method and apparatus for causing an open circuit in a conductive line".
  3. "IBM eFuse to yield self-repairing, self-regulating CPUs".
  4. "Examining metal eFuses".
  5. (2004-07-30). "IBM introduces chip morphing technology". IBM.
  6. Port, Otis. (2005-06-06). "Mighty Morphing Power Processors". [[BusinessWeek]].
  7. (2023-06-08). "Espressif ESP-IDF esp_mac.h". Espressif.
  8. Amadeo, Ron. (2022-08-31). "Google gives developers a way to sidestep Android 13's one-way update".
  9. (2007-02-13). "IBM System z9 eFUSE applications and methodology". IBM Journal of Research and Development.
  10. "Understanding the Xbox 360's Fusesets".
  11. Speedy22. (2006-03-07). "XBOX 360 CPU Datasheet. Version 1.5.".
  12. (2005-10-25). "IBM delivers Power-based chip for Microsoft Xbox 360 worldwide launch". IBM.
  13. "What is a Knox Warranty Bit and how is it triggered?".
  14. "E-fuses".

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::

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