Parasitic capacitance

About: Parasitic capacitance is a research topic. Over the lifetime, 10029 publications have been published within this topic receiving 110331 citations.

Stray capacitances of single-layer air-core inductors for high-frequency applications

Abstract: A method for predicting stray capacitances of HF inductors dependent on their geometry is presented The analysis is performed for inductors made of one layer of turns with circular and rectangular cross-sections The wire is uniformly wound around a cylindrical nonferromagnetic core The method is based on an analytical approach to obtain the turn-to-turn and turn-to-shield capacitances of coils The influence of insulating coatings of the wire is also taken into account An overall equivalent stray capacitance is derived according to the typical HF equivalent lumped parameter circuit of inductors The method was tested with experimental measurements and the accuracy of the results was good in most cases The derived expressions are useful for designing of HF inductors and can be also used for simulation purposes

Self-Capacitance of Single-Layer Inductors With Separation Between Conductor Turns

Abstract: This letter presents the technique for estimating the self-capacitance of single-layer air-core solenoid inductors with separation between the insulated turns. In single-layer air-core inductors, the self-capacitance is due to the conductor turn-to-turn capacitances. The analytical framework to determine the turn-to-turn capacitances of single-layer air-core inductors with uniformly and nonuniformly separated conductor turns is established. The influence of the wire insulation coating is taken into consideration. A representative design example of a single-layer air-core inductor is presented and its self-capacitance and self-resonant frequency are predicted. The presented analytical approach was tested by experimental measurements on the designed inductor. The derived analytical expressions are useful for designing air-core inductors for high frequency (HF) and very HF applications such as electromagnetic interference/electromagnetic compatibility filters and radio and TV transmitters.

Universal MEMS platforms for passive RF components: suspended inductors and variable capacitors

Abstract: We propose a universal MEMS technology platform for fabricating integrable passive components for radio frequency (RF) integrated circuits. This platform is based on a novel surface-micromachined Micro-Elevator by Self-Assembly (MESA) technique. Both high-Q inductors and variable capacitors can be realized by the MESA technology. A surface-micromachined spiral inductor that is raised by 250 /spl mu/m above the Si substrate has been experimentally demonstrated. The suspended inductor has less parasitic capacitance and substrate loss, and higher quality (Q) value and resonant frequency. The inductance of a 12.5-turn inductor is measured to be 24 nH. The results show that the self-assembled passive RF elements are suitable for monolithic integration.

Power source for electric discharge machining

Abstract: A power source for electric discharge machining, which performs a semi-mirror-finish machining operation with a surface roughness of 1 μm Rmax or less. The power source includes either a resonance circuit or an impedance matching circuit so that the electric discharge is carried out under the condition that resonance is caused to occur with the capacitance of an interelectrode gap between an electrode and a workpiece to be machined or the impedance-matching is effected in response to variation in interelectrode condition. With such a power source, it is possible to eliminate the effect of the stray capacitance exsiting in a current supplying line and also to eliminate the shortcoming due to variation on the interelectrode condition, and therefore a mirror-finished machining operation can be stably carried out to provide machined surfaces excellent in surface roughness.

A low-power wide-band amplifier using a new parasitic capacitance compensation technique

Abstract: A 3-mW 800-MHz amplifier with a voltage gain of 10 dB is discussed. The parasitic junction capacitance of a transistor is the major factor limiting the bandwidth particularly for low-power amplifiers. In addition to the pole at the input node, the pole at the output node may become dominant in low-power amplifiers, which use high-speed bipolar transistors. A parasitic capacitance compensation technique to expand the bandwidth in this type of amplifier is discussed. This technique compensates for both capacitances at the input and output nodes and enhances the bandwidth and the gain-bandwidth product. The measured data demonstrate that this technique expands the bandwidth to about twice that of a conventional differential amplifier. In addition, circuit simulation predicts that this technique expands the bandwidth by about 40% over a conventional peaking technique. A stable frequency response without any overpeaking or oscillation problem has been achieved by utilizing the parasitic junction capacitances of dummy transistors as the compensation capacitance. >