The device comes in a 2- by 2-mm dual flat no-lead (DFN) 8L flip-chip or plastic package.
The chip operates with a supply voltage of 2.4 to 3.0 V with current consumption in the 20- to 100-♚ range, unlike others. The frequency range is up to 3 GHz, and power handling is up to 40 dBm. Capacitor Q's greater than 100 are possible. Typical switching speed is less than 5 µs. The capacitor values can range from 0.5 to 10 pF with typical tuning ratios of 3:1 to 6:1, or 10:1 in some cases.
#Other words for variables serial
The DuNE digitally tunable capacitor (DTC) chip contains five capacitors switched by MOSFETs that operate from a serial input bus with a 5-bit code providing 32 possible capacitor values. This section reads like a news release and needs to be rewritten.Ī digitally tuned capacitor is a type of chip-form variable capacitor patented by Peregrine Semiconductor in the form of DuNE technology using UltraCMOS process and HaRP design innovation. Varicaps are used for frequency modulation of oscillators, and to make high-frequency voltage controlled oscillators (VCOs), the core component in phase-locked loop (PLL) frequency synthesizers that are ubiquitous in modern communications equipment.
#Other words for variables tv
in FM Radio or TV tuners, dynamic range is limited by noise rather than large signal handling requirements, and varicaps are commonly used in the signal path. Their use is limited to low signal amplitudes to avoid obvious distortions as the capacitance would be affected by the change of signal voltage, precluding their use in the input stages of high-quality RF communications receivers, where they would add unacceptable levels of intermodulation. Any diode exhibits this effect (including p/n junctions in transistors), but devices specifically sold as variable capacitance diodes (also called varactors or varicaps) are designed with a large junction area and a doping profile specifically designed to maximize capacitance. The thickness of the depletion layer of a reverse-biased semiconductor diode varies with the DC voltage applied across the diode. In addition to air and plastic, trimmers can also be made using a ceramic dielectric. Small variable capacitors operated by screwdriver (for instance, to precisely set a resonant frequency at the factory and then never be adjusted again) are called trimmer capacitors. This has practical advantages for makeshift or home construction and may be found in resonant loop antennas or crystal radios. A variant of this structure that allows for linear movement of one set of plates to change the plate overlap area is also used and might be called a slider. These so-called squeezers can’t provide a stable and reproducible capacitance, however. Very cheap variable capacitors are constructed from layered aluminium and plastic foils that are variably pressed together using a screw. Vacuum variables can also be more convenient since the elements are under a vacuum the working voltage can be higher than an air variable the same size, allowing the size of the vacuum capacitor to be reduced. The most common usage for vacuum variables are in high powered transmitters such as those used for broadcasting, military and amateur radio as well as high powered RF tuning networks. The vacuum not only increases the working voltage and current handling capacity of the capacitor it also greatly reduces the chance of arcing across the plates. A screw shaft is attached to the plunger, when the shaft is turned the plunger moves in or out of the sleeve and the value of the capacitor changes. The movable part (plunger) is mounted on a flexible metal membrane that seals and maintains the vacuum. These plates are then sealed inside of a non-conductive envelope such as glass or ceramic and placed under a high vacuum. A vacuum variable capacitor uses a set of plates made from concentric cylinders that can be slid in or out of an opposing set of cylinders (sleeve and plunger).
to spread the variation of capacity over a larger angle, often several turns. Various forms of reduction gear mechanisms are often used to achieve finer tuning control, i.e. By choosing the shape of the rotary plates, various functions of capacitance vs. Air or plastic foils can be used as dielectric material. The most common form arranges a group of semicircular metal plates on a rotary axis (“rotor”) that are positioned in the gaps between a set of stationary plates (“stator”) so that the area of overlap can be changed by rotating the axis. In mechanically controlled variable capacitors, the distance between the plates, or the amount of plate surface area which overlaps, can be changed.
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