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what is a zener diode used for

来源:LM317 Electronics Components编辑:Taica Corporation时间:2021-06-15 15:09:53

Due to high on-chip tuning capacitance, the LRI2K and LRIS2K also support the design of very small antennas. This can save space, making theses IC suitable for use with small objects, such as pharmaceutical medicine bottles. What's more, thanks to their long reading range, an EAS (Electrical Article Surveillance) feature can be implemented for point-of-sale applications.

In the project called NGN PlaNetS, researchers from Munich-based Fraunhofer-Einrichtung für Systeme der Kommunikationstechnik (ESK) and the Paderborn University, along with Infineon Technologies, design and test prototypes for next-generation internet content distribution. The projects aims at eliminating time delays and jitter in ethernet networks and thus enable this network category to connect to the internet and carry out Internet Protocol (IP) distributions.

The research work does not only focus on prioritizing critical data packets but also on intelligent switching: The researchers developed algorithms that automatically select an alternative route through the network if one mesh renders overloaded. Presently, the project is at a stage when industry partners test the scheme in a prototype implementation, Fraunhofer said.

what is a zener diode used for

Portland, Ore. — AVX Corp. has made what it claims is a revolutionary step backward with its invention of a patented new land-grid array (LGA) architecture for decoupling capacitors.

Decoupling capacitors provide on-demand power reserves that can keep the edges sharp on the quickly changing signals from high-speed microprocessors, graphics coprocessors, digital signal pro- cessors and field-programmable gate arrays. Unfortunately, as clock frequencies have climbed, capacitor designers have quelled the parasitic inductance that can limit switching speed by resorting to hard-to-use multilayer architectures that require terminals that exit from the side.

AVX has lowered parasitic inductance by returning to the simpler design of old-school capacitors, which feed directly into the printed-circuit board from the bottom.

what is a zener diode used for

Our new land-grid array decoupling capacitors offer higher-frequency performance in a simpler package that lowers assembly costs, with terminals that exit from the bottom,” said Craig Hunter, strategic-marketing manager at AVX (Myrtle Beach, S.C.). The decoupling capacitors offer as low an inductance as harder-to-use components with multiterminals that exit from the side,” Hunter said.

Most capacitors are just parallel metal plates separated by an insulator, and hence have essentially no inductance. In working capacitors, however, parasitic inductance is a fact of life. When current flows, the flux creates a magnetic field that loops around the internal electrodes of the capacitor and its external termination, the power planes, vias, mounting pads and solder fillets of the printed-circuit board.

what is a zener diode used for

Current strategiesTo date, two strategies have been used to reduce parasitic inductance. First, the capacitor is made in the shape of a rectangle instead of a square. The shorter distance between the terminals exiting the side of the capacitor along the narrow dimension makes the loop smaller. The long dimension of the rectangle, called the span, is perpendicular to the direction of current flow and thus does not contribute to the part's inductance.

The second strategy has been to reduce loop area further by using smaller plates in multiple layers. Not only is the distance between terminals smaller with this approach, but because the current path of the lowest loop has the least resistance, it also pins the inductance for the whole part on the area of the bottom layer loop. AVX offers high-performance decoupling capacitors that combine both strategies.

Turbo mode adds speedThe follow-on is a more-flexible platform that benefits from the design team's better understanding of the external bill of materials, such as the filter requirements. The developers also added more interfaces, such as GMII and MII ports, allowing the EN2210 to work as an equivalent Ethernet PHY. The MII includes a turbo mode that boosts throughput to 200 Mbits/second. Also on board are FlexBus and PCI host interfaces.

Though the PHY is rated at 270 Mbits/s, real throughput is just north of 100 Mbits/s. That's enough to handle a few compressed high-definition streams, plus voice, data and the associated overhead.

Graham said the c.LINK platform also supports a 50 percent increase in data rate through packet aggregation to allow continued evolution of the standard.

To improve quality-of-service, Entropic has added features such as parameterized constant-bit-rate, parameterized variable-bit-rate and prioritized traffic. These could be critical in preventing data from hogging bandwidth in a video-centric environment, especially if operators decide to open up their home networks to data-centric networked devices.

A couple of other new twists include using the chip as a standalone networking solution in the low-RF range or using it at baseband frequencies of less than 50 MHz. Typically, MoCA streams use RF frequencies between 850 and 1,500 MHz, but Graham said that some telco operators are interested in the lower frequency, despite its greater susceptibility to interference.

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