ANTIFUSE PROGRAMMING FPGAS PDF

FPGA (Field Programmable Gate Array) is an integrated circuit FPGA devices are produced by a number of semiconductor basic modes of programming: Antifuse-based FPGAs are different from the previous ones in that they can be. That is where the Field Programmable Gate Arrays (FPGAs) become of interest! They are hardware The antifuse programming technology is the simplest one. ❖The Programming technology. ❖The basic logic cells. ❖The I/O logic cells. ❖ Programmable interconnect. ❖Software to design and program the FPGA.

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FPGAs in computer

For example a precision resistor can be manufactured by forming several series resistors with Zeners in parallel oriented to be nonconductive during normal operation of the device and then shorting selected Zeners to shunt the unwanted resistors. Certain programmable logic devices PLDssuch as structured ASICsuse antifuse technology to configure logic circuits and create a customized design from a standard IC design.

The p-n junction that serves as such diode is overloaded with a current spike and overheated. When the bulb blows, the entire mains voltage is applied across the single blown lamp. With a poly-diffusion antifuse, the high current density creates heatwhich melts a thin insulating layer between polysilicon and diffusion electrodes, creating a permanent resistive silicon link. This rapidly causes the antifuse to short out the blown bulb, allowing the series circuit to resume functioning, albeit with a larger proportion of the mains voltage now applied to each of the remaining lamps.

In some cases a combined circuit with zeners and transistors can be used to form a zapping matrix; with additional zeners, the trimming which uses voltages higher than the normal operational voltage of the chip can be performed even after packaging the chip. The terminals of the antifuses are usually accessible as bonding pads and the trimming process is performed before wire-bonding and encapsulating the chip.

Unlike Christmas lights, the circuit usually contained an automatic device to regulate the electric current flowing in the circuit, preventing the current from rising as additional lamps burned out. As the number of bonding pads is limited for a given size of the chip, various multiplexing strategies are used for larger number of antifuses.

Antifuses are best known for their use in mini-light or miniature style low-voltage Christmas tree lights. A specialized structure optimized for the purpose can be employed where the antifuse is an integral part of the design. One approach for the ICs that use antifuse technology employs a thin barrier of non-conducting amorphous silicon between two metal conductors.

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Whereas a fuse starts with a low resistance and is designed to permanently break an electrically conductive path typically when the current through the path exceeds a specified limitan antifuse starts with a high resistance and is designed to permanently create an electrically conductive path typically when the voltage across the antifuse exceeds a certain level. The resulting resistance of the junction is in the range of 10 ohms. Articles needing additional references from May All articles needing additional references.

Occasionally, the insulation fails to break down on its own, but tapping the blown lamp will usually finish the job. The spike is formed on and slightly below the silicon surface, just below the passivation layer without damaging it. This page was last edited on 7 Julyat Amorphous silicon is a material usually not used in either bipolar or CMOS processes and requires an additional manufacturing step.

Each individual street-lamp was equipped with a film cutout ; a small disk of insulating film that separated two contacts connected to the two wires leading to the lamp.

Antifuse – Wikipedia

Zener diodes can be used as antifuses. Often a special bulb with no antifuse and often a slightly different rating so it blows first as the voltage gets too high known as a “fuse bulb” is incorporated into the string of lights to protect programmnig the possibility of severe overcurrent if too many bulbs fail.

Their disadvantage, however, is lower area efficiency compared to other types. This programming, performed after manufacturing, is permanent and irreversible. They are historically used especially with bipolar processes, where the thin oxide needed for dielectric antifuses anifuse not available. The insulation of the antifuse wire withstands the ordinary low voltage imposed across a functioning lamp but rapidly breaks down under the full mains voltage, giving the antifuse action.

Anifuse Corporation refers to their antifuses as “ViaLinks” because blown fuses create a connection between two crossing layers of wiring on the chip in the same way that a via on a printed circuit board creates a connection between copper layers. Antifuses are widely used to permanently program integrated circuits ICs.

Progdamming the same fashion as with the Christmas lights described above, if the lamp failed, the entire voltage of the street lighting circuit thousands of volts was imposed across the insulating film in the cutout, causing it to proogramming. The antifuse is made using wire with a high resistance coating and this wire is coiled over programning two vertical filament support wires inside the bulb.

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Zener zap is frequently employed in mixed-signal circuits for trimming values of analog components. By using this site, you agree to the Terms of Use and Privacy Policy.

This article needs additional citations for verification. The larger, traditional, C7 and C9 style lights are wired in parallel and are rated to operate directly at mains voltage.

The parallel resistors cannot have too low value as that would sink the zapping current; a series-parallel combination of resistors and antifuses is employed in such cases. By this approach, it is possible only to lower the value of the resulting resistor.

Dielectric antifuses employ a very thin oxide barrier between a pair of conductors. In this way, the failed lamp was bypassed and illumination restored to the rest of the street. From Wikipedia, the free encyclopedia. Ordinarily for operation from mains voltagesthe lamps are wired in series.

Antifuses may be used in programmable read-only memory PROM. Please help improve this article by adding citations to reliable sources. They may be less susceptible to alpha prgramming which can cause circuits to malfunction.

When the failed lamp was finally changed, a new piece of film was also installed, once again separating the electrical contacts in the cutout.

The antifuse is usually triggered using an approximately 5 mA current. A standard NPN transistor structure is often used in common bipolar processes as the antifuse. May Learn how and when to remove this template message. When a sufficiently fpgass voltage is applied across the amorphous silicon it is turned into a polycrystalline silicon-metal alloy with a low resistancewhich is conductive.

In a similar fashion to that of Christmas tree lights, before the advent of high-intensity discharge lampsstreet light circuits using incandescent light bulbs were often operated as high-voltage series circuits. This technology has many applications. Each bit contains both a fuse and an antifuse and is programmed by triggering one of the two. Also circuits built via the antifuse’s permanent conductive paths may be faster than similar circuits implemented in PLDs using SRAM technology.