May 14, 2019

A resettable fuse is a polymeric positive temperature coefficient (PPTC) device that is a passive electronic component used to protect against overcurrent faults in electronic circuits. The device is also known as a multifuse or polyfuse or polyswitch. . Beam deflection tube · Charactron · Iconoscope · Magic eye tube. Read about ‘F1/F2 polyfuses gone’ on elementcom. are made to the Raspberry Pi’s hardware in the future and how they are justified by. Isoloop magnetic couplers 6) Working 7) Digital isolators 8) Advantages 9) Applications 10) Future scope 11) conclusion 12) References; 3.

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future of polyfuse pdf download

This subcircuit remains reasonably accurate as long as the tank resistance is relatively small compared to the resistance of R1. Comparison of Available Resistors length causes significant errors in the sense voltage. These rules assume 25 sheet variation and a linewidth control of 20 of the minimum feature size.

Alternatively, the value of the resistor can be continuously monitored and the trim halted once the desired resistance has been achieved. Temperature Variation Resistivity depends on temperature in a complex, nonlinear manner. These devices were first discovered and described by Gerald Pearson at Bell Labs in and described in US patent 2, If available, these should be used when calculating resistor values.

Resettable fuse – Wikipedia

High-Sheet Resistors High-sheet-resistance HSR implants are available as extensions for most standard bipolar processes. The silicided portions at either end of the resistor perform the same function as the NSD-doped heads of the high-sheet poly resistor Figure 5.

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The smaller sheets such as are of little value because they cannot save enough die area to justify their cost. Considerable space can be saved by eliminating the base diffusion Figure 5. Because larger voltages are generally required to program Zeners than fuyure, care must be taken to ensure that the circuitry connected to the trim network can withstand a momentary overvoltage condition.

The Zeners must be oriented so that they remain reverse-biased during normal operation, and the voltage placed across each Zener must not exceed the base-emitter breakdown voltage. This problem is usually overcome by enlarging the ends of the resistor to form heads around the contacts. Ohmic contact cannot be made directly to the HSR implant because it is both too lightly doped and too shallow, so the heads of the resistor consist of base oplyfuse. Poly resistors sxope reside on top of field oxide.

The Art of Analog Layo Resistor Parasitics Because contact resistances are strongly process-dependent, these values are only indicative of what any given fab can actually guarantee. Each square polyvuse adds approximately 0. Circuit designers can help minimize the impact of fuse programming transients by placing the on the least-vulnerable end of.

Trimming Resistors Resistors can be trimmed using fuses, Zener zaps, or laser trims. These resistors polyfsue not require contacts since the thin-film material is deposited immediately prior to the uppermost layer of metallization.

Perhaps the Pi can manage how much power may go to the USB connectors.

Polyfhse ejected aluminum tends to splatter onto the probe needles and eventually fouls them so badly that shorts occur. For example, a standard bipolar process with a minimum feature size of 5 u m will probably have a linewidth control of about 1um.


Design a polysilicon fuse. The use of refractory barrier metal significantly increases contact resistance variability due to sintering problems. The width bias applies to the HSR implant forming the resistor body, while the length bias applies to the separation between the base heads. Adjusting Resistor Values Even if programming does not result in a clean open circuit, it almost invariably causes resistance changes that can be detected in this manner.

Via values are the author’s estimate. The voltage modulation of epi pinch devices is so severe that they are rarely used as ordinary resistors. This can be achieved by connecting the base diffusion to the low-voltageend of the resistor and connecting the tank to the high-voltage end.

The plastic seals futute opening over the fuse and prevents the conductive material from being ejected. Self-Healing Polymers and Polymer Composites. The protective overcoat remains intact since the material does not actually melt or vaporize.

Resettable fuse

In extreme cases, the base may succeed ot punching entirely through a narrow N-well resistor, causing it to appear as an open circuit. The polysilicon is laid out as a small resistor connecting two bondpads.

The dimensions of a resistor polyfsue because of photolithographic inaccuracies and nonuniform etch rates. Make all resistors from one or more segments to ensure precise matching.