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optimised to support multiple applications. These include notebooks, mobile routers, and low-power customer premises systems.
The RFFM4501E integrates a +17.5dBm (80MHz MCS9) PA at 3.3V, a low insertion loss/high isolation single pole two throw (SP2T) switch, harmonic filtering, and a low noise amplifier (LNA) with bypass mode, for equipment manufacturers seeking to adjust receive sensitivity.
The receive chain provides 12.5dB of typical gain with only 12mA of current and an excellent noise figure of 2.5dB. Separate Rx/Tx 50 Ohm ports simplify matching and provide input and output signals for both the transmit and receive paths.
The RFFM4501E is optimised to mate with the 802.11ac chipset of a leading semiconductor company.
The ultra-small form factor (3mm x 3mm x 1.1mm) and high level of integration of the RFFM4501E shrink the product footprint, reduce external component count, minimise assembly costs, speed time-to-market.
SiC could eclipse diamond in quantum computers
By creating a silicon vacancy defect in silicon carbide, scientists have generated additional energy levels in the so band gap for use in supercomputers
Researchers from the University of Würzburg have modified SiC crystals to exhibit new and surprising properties.
This makes them interesting with regard to the design of high-performance computers or data transmission.
SiC crystals consist of a regular lattice formed by silicon and carbon atoms. At present, these semiconductors are extensively used in micro and optoelectronics. They are particularly suited for used in high temperature applications in power semiconductors.
Now physicists from Saint Petersburg and the University of Würzburg have succeeded in
A combination of light and radio waves can be used to store and retrieve information in silicon vacancy defects. (Graphics: Georgy Astakhov)
A defect in the crystal
“We have removed a silicon atom from the crystal lattice, thus creating a silicon vacancy defect,” Georgy Astakhov says, explaining the method applied by the physicists. Astakhov is a research fellow at the Department for Experimental Physics VI of the University of Würzburg.
To the researchers’ surprise, this crystallographic defect gives the material interesting new properties. In order for the semiconductor to emit light, its electrons must be raised to a higher energy level by means of energy-rich light, for instance. The silicon vacancy defect leads to the generation of additional energy levels in the so-called band gap.
Stepladder for electrons
Vladimir Dyakonov, chair of the Department for Experimental Physics VI, explains the process with a simple analogy; “In a regular, perfectly structured silicon carbide crystal, the electron must overcome a big hurdle with only one step. This requires a lot of energy. Due to the defect, the electron is provided with a ladder. It can clear the hurdle with two steps, requiring less energy.”
When the electrons “fall back” from the higher energy level to the lower one, this type of silicon carbide emits infrared rather than ultraviolet light.
January/February 2013
www.compoundsemiconductor.net 125
manipulating SiC in a way so it can be used in novel, super-fast quantum computers.
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