Based on AVX Proprietary RFAP thin-film technology, the LP0402N series harmonic low-pass filters from AVX Corp. are ideally suited to applications in wireless communications, WLANs, GPS and WiMAX. A key benefit of these filters is their tiny 0402 package size coupled with significantly better RF performance than larger Low Temperature Co-fired Ceramic (LTCC) devices.
The LP0402N series is currently available in three frequencies: 3.5, 5.2 and 5.5 GHz. The low-pass filters exhibit high attenuation of 30 dB at second and 20 dB at third harmonics. Operating temperature range is -40 to 85 degrees Celsius. The filters feature Land Grid Array (LGA) terminations to minimize parasitic inductance, while providing further benefits such as inherent low profile, self-alignment during reflow soldering, excellent solderability and better heat dissipation. Terminations are Nickel with a lead-free solder coating compatible with automatic soldering technologies. RFAP is a proprietary AVX technology based on modified semiconductor technologies including metal sputtering, photolithography, plasma-etched chemical vapor deposition (PECVD) and accurate plating. Low-temperature PECVD builds a highly stable silicon dioxide dielectric on a semiconductor wafer, while metal lithography, in combination with dry etch, ensures precise geometry of the metal elements.
The thin-film silicon dioxide dielectric is much thinner, around 1 μm compared to LTCC of 50 to 250 μm, which enables much higher capacitance density. This by far outweighs the low dielectric constant of thin-film. In addition, the conductors used for the electrodes have lower resistivity (of the order of 1 milliohm per mm square) than LTCC counterparts (10 to 20 milliohms per mm square). This allows for higher RF-power handling.
RFAP technology enables smaller, more precise devices with better RF performance, superior temperature stability, high levels of repeatability, better termination compatibility with SMD processes and flexibility for design engineers.