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.
|Published (Last):||15 November 2009|
|PDF File Size:||16.97 Mb|
|ePub File Size:||6.29 Mb|
|Price:||Free* [*Free Regsitration Required]|
Connections that do not tie back to the positive end of the resistor nor to a supply should be carefully analyzed for sneak conduction paths similar to this one. An NBL overlap of 5 to 8um will usually suffice. Otherwise, the NSD implantation need only overlap the contacts sufficiently to ensure electrical continuity. This problem is usually overcome by enlarging the ends of the resistor to form heads around the contacts.
Linewidth control of submicron features depends quite strongly on the precise dimensions of the geometry, but submicron resistors are rarely employed.
Second-metal leads can route over a resistor placed on first metal, but first-metal or poly leads should not route beneath a resistor placed on second metal because they may introduce nonplanarities in the resistor. Unless the circuitry futire specifically designed to switch at low voltages, the look-ahead process may overstress the poly fuse, causing it to increase in value to the point where it can no longer be reliably programmed.
HSR implants come in a range of sheet resistances. A large current flows through the fuse in the instant before it blows, and the sudden interruption of this current can cause voltage transients due to parasitic inductances. The heterogeneous nature of polysilicon also affects its temperature coefficient ufture resistivity.
future of polyfuse pdf download
See also discussion and curves ot various diffusions in amilton,et al. So here we propose an automatic wiper system that automatically switches ON on detecting rain and stops when rain stops.
In extreme cases, polysilicon resistors may experience a phenomenon similar to what occurs in Zener zaps. If CMOS transistors are available, then these can be used as switches to reconfigure the resistor network. Some designers have attempted to use remotely programmed poly fuses to implement look-ahead trimming.
Design a polysilicon fuse. If too much current is passed through the device the device will begin to heat.
All HSR resistors operating at voltages approaching or exceeding the thick-field threshold require careful field plating. Wednesday 16th of August HSR resistors can be merged with other devices in a common tank providing that none of the merged devices inject minority carriers into the shared tank. Reducing the number of trimpads saves die area and reduces the cost of the integrated circuit.
The value of the resistor equals where Rs is the sheet resistance of the HSR implant, Wb is the width bias, and Lb is the length bias. Suppose that a poly resistor must support a voltage differentialof 5V. This tankless style of emitter resistor can also be constructed in standard bipolar by coding base entirely across the tank that contains an emitter resistor.
D1 and D2 each model half of the total area of the resistor-tank junction, while D3 models the full area of the tank-substrate junction.
NSD implants coded around either end of the resistor produce lowresistivity heads for the contacts.
Tweakable resistors can drastically reduce the time required to obtain fully parametric devices. Retrieved 31 August Assuming that transistor Q 1 always conducts, the tank of R5 will be biased one base-emitter drop above the positive terminal of scole resistor.
A resistor dissipates power equal to the product of the voltage across it and the current through it. The rate of carrier drift in weak electric fields is proportional to the electric-field intensity.
The networks used for laser trimming are similar to those shown in Figure 5.
Resettable fuse – Wikipedia
The total resistance equals the sum of the resistances of each segment. The resistance of the base heads is difficult to predict because of nonuniform current flow.
Notice that futurd high-voltage end of the resistor narrows slightly.
Resistors to allow programming. In a dogbone resistor, the current spreads out as it enters the head, and the effective value of the resistor decreases. The approximate value of the 7 8 Glaser,et al. The metal leads contacting each head of the resistor should extend to cover the exposed portions of the N-well.
The USB specifications say that all USB ports must be protected, but the protection may not be permanent, that is may not require human intervention to recover. The probe card may require occasional cleaning to alleviate this problem.
Nonlinearity Ideal resistors exhibit a linear relationship between voltage and current. Usual problem – USB power has gone.