Malvern, Pa. - Vishay Intertechnology Inc. believes its silicon-based surface-mount RF capacitors represent a technology breakthrough, offering wireless-design engineers improvements in electrical performance in a small package. Silicon-based RF capacitors can replace standard RF capacitor technologies such as LTCC multilayer chip caps and thin-film capacitors, the company said.
These high-performance, high-precision devices are said to offer higher self-resonant frequencies (SRFs), lower parasitic inductance, lower equivalent-series resistance and tighter tolerances than other capacitor technologies, as well as higher capacitance and high Q factors-all in a 0402-size package.
Vishay turned to silicon process technologies primarily because passive-component technologies have made fewer advances in the past several years than semiconductor processes, said Haim Goldberger, vice president of the Integrated Products Division.
Vishay claims the HPC0402A parts are the industry's first silicon-based RF capacitors and the first 0402-size devices to provide high accuracy over 22 picofarads. Built on a proprietary Vishay process and standard semiconductor processes, these capacitors are said to deliver excellent stability over a wide frequency range with a broad range of capacitance values: 0.6 to 180 pF, with tolerances to plus/minus 1 percent or 0.05 pF.
The capacitor's construction enables a reduction in the distance between components, reducing parasitic lines and improving circuit performance, said the company. The design also delivers ultrahigh SRF, which differentiates the capacitor from comparable products by offering extremely stable capacitance at frequencies ranging from 1 MHz up to several gigahertz, Vishay said.
The device's bump structure also provides several benefits. It eliminates tombstoning, provides a flat top area for better pick-and-place assembly and allows board size reductions of up to 45 percent, the company said.
The parts are available in 6-, 10-, 16- and 25-volt options. The temperature coefficient of capacitance is plus/minus 30 ppm/ degrees C over an operating-temperature range of -55 degrees C to 125 degrees C. Other features include a lifetime of 1,000 hours at 125 degrees C at twice the rated power, and resistance to moisture and shock.
The new devices can be used in a variety of applications including wireless communications, mobile and cordless phones, GPS equipment, voltage-controlled oscillators, filter networks and matching networks.
Pricing (U.S. delivery) for a design kit that includes 16 components (1.2 to 22 pF) is $125. Samples are available now, with lead times up to eight weeks.
Call (610) 251-5287