eFuse
Incomputing,aneFuse(electronic fuse) is a microscopicfuseput into acomputer chip.This technology was invented byIBMin 2004[1]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.[2]
Mechanism of action[edit]
eFuses can be made out of silicon or metal traces. In both cases, they work (blow) byelectromigration,the phenomenon that 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.[3][4]
Uses[edit]
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.[3][5][6]Today, most eFuses are used to etchserializationor calibration data onto a chip thus making it a read-only value.[7]
Descriptive term[edit]
eFuses are perhaps more commonly used as a one-timeprogrammable ROMor write-restricted memory, and not actual physical electric fuses. This ranges from writing unique information onto CPUs,[4]or in the case of game consoles and other restricted hardware, preventing downgrades by permanently recording a newer version. TheXbox 360,Nintendo Switch,Pixel 6andSamsung Galaxy S22are known for using eFuses this way.[8]
Implementations[edit]
eFuses used for performance adjustment or unique IDs:
- IBMPOWER5andPOWER6high-endRISCprocessors; probably all newer models[3]
- IBM System z9andSystem z10mainframeprocessors[9]
- Sony/Toshiba/IBMCellused inPlayStation 3.Not claimed to be used for downgrade prevention.
- IntelWestmereCPUs; probably all newer models[4]
- TIMSP430MCUfamily for Unique IDs.
- TIFPD-LinkSERDESfor a variety of different settings.
eFuses known to be used for hardware restriction:
- IBM/MicrosoftXenonCPU in theXbox 360game console. 768 bits of fuses.[10][11][12]
- Samsung Knoxdevices use an eFuse to detect if a non-Samsung boot path has ever been run.[13]
Variants[edit]
Resettable eFuses are used for protecting circuits. They act similarly toresettable fuses,and are generally shipped as a standalone chip package.[14]
There are several ways of implementing anantifusein silicon: seeAntifuse § Antifuses in integrated circuits.
See also[edit]
References[edit]
- ^"IBM's eFuse technology portends adaptable chips".
- ^DCC (1989-03-14)."Method and apparatus for causing an open circuit in a conductive line".Archived fromthe originalon 2017-02-11.
- ^abcSmith, Tony."IBM eFuse to yield self-repairing, self-regulating CPUs".The Register.
- ^abc"Examining metal eFuses".EETAsia.Archived fromthe originalon 2021-06-14.Retrieved2020-12-30.
- ^"IBM introduces chip morphing technology".IBM. 2004-07-30. Archived fromthe originalon 2010-07-24.Retrieved2009-09-17.
- ^Port, Otis (2005-06-06)."Mighty Morphing Power Processors".BusinessWeek.Archived fromthe originalon May 29, 2005.
- ^"Espressif ESP-IDF esp_mac.h".Espressif. 2023-06-08.Retrieved2023-11-07.
- ^Amadeo, Ron (2022-08-31)."Google gives developers a way to sidestep Android 13's one-way update".Ars Technica.Retrieved2022-09-04.
- ^Rizzolo, R. F.; Foote, T. G.; et al. (2007-02-13)."IBM System z9 eFUSE applications and methodology".IBM Journal of Research and Development.51:65–75.doi:10.1147/rd.511.0065.Retrieved2007-02-28.
- ^"Understanding the Xbox 360's Fusesets".Free60 Wiki.
- ^Speedy22 (2006-03-07)."XBOX 360 CPU Datasheet. Version 1.5"(PDF).Archived fromthe original(PDF)on 2006-03-15.Retrieved2007-02-28.
{{cite web}}:CS1 maint: numeric names: authors list (link) - ^"IBM delivers Power-based chip for Microsoft Xbox 360 worldwide launch".IBM. 2005-10-25. Archived fromthe originalon 2007-03-11.Retrieved2007-02-28.
- ^"What is a Knox Warranty Bit and how is it triggered?".docs.samsungknox.com.Retrieved2024-07-16.
- ^"E-fuses".STMicroelectronics.