News and New Products

Passives step up to meet gigahertz needs

By Bill Schweber, Executive Editor -- EDN, 8/23/2005

It’s not just ICs that are getting faster; their critical support passives have to move up in bandwidth, as well. The GZ capacitor series from AVX Corp provides dc-blocking operation at the 15-kHz to 40-GHz bandwidth that optical transceivers use. The surface-mount, MLCs (multilayer capacitors) use Ni-Al (nickel-aluminum) terminations and feature resonance-free performance of less than 0.5-dB dip through at least 26.5 GHz. Their footprints match the 0.015-in. (0.38-mm) and 0.020-in. (0.51-mm) microstrip-line-design widths that are common in pc boards for these frequencies. Prices range from $1 to $4.

Featuring high Q and low ESR (equivalent series resistance), the company also offers 0603-sized units based on porcelain and ceramic MLC design. The SQCS series has capacitance of 0.1 to 100 pF. The 250V units target use in 1 MHz to 10 GHz applications, and they also sport the much-desired NPO characteristic of stable specifications over an operating-temperature range of –55 to +125°C. They sell for 4 to 50 cents, depending on value and volume.

For inductance values of 0.82 to 6.8 nH, the gigahertz-range SQ series uses thin-film technology in 0402-sized land-grid-array cases. According to product manager Larry Eisenberger, “This is the thin-film equivalent of wire-wound inductors, capable of any value in the range, at tolerances that are much tighter than those offered by wire-wound.” The SQ Series devices sell for 10 to 30 cents.