Kyocera Corp. has developed an RF SAW filter for advanced mobile handsets in a chip-scale package measuring 1.6 x 1.4 x 0.6mm, believed by the company to be the industry's smallest.
Kyocera's SF16 SAW filter is designed for use with PCS, cellular, and GPS bands with respective operating frequencies of 1.9GHz, 800MHz, and 1.5GHz. The part is compatible with Qualcomm Inc.'s MSM6000 series CDMA chipsets for cell phones, and adds to Kyocera's growing line of components for CDMA applications that include VC-TCXOs, VCOs, and Bluetooth modules.
Kyocera now has a 5% share of the global SAW filter market, according to Taro Hishinuma, product manager of Kyocera Developed Products for the Japanese company's U.S. subsidiary, AVX Corp., Myrtle Beach, S.C. "With the SF16, we're looking to increase our market share to 20%," he said.
Hishinuma added that the filter's small chip-scale package is a result of enhancements in the company's substrate and sealing technology. Instead of mounting the SAW chip onto a ceramic package, the company flip-chip-mounts the filter onto a ceramic substrate, seals it, and then applies a high-temperature resin coating.
This design reduces the size and footprint of the filter by greater than 50% compared with filters from Epcos and Fujitsu, according to Kyocera, while providing protection against mechanical shock. In addition, the chip-scale design simplifies the filter's inner wiring to reduce parasitic impedance and improve attenuation at bandwidths above 3GHz, Kyocera said.
Specifications for the SAW filter include a bandwidth insertion loss of 1.8 to 4.1dB, ripple of 0.7 to 2dB, and voltage standing wave ratio of 2.5V. Attenuation is 30dB at DC to 824MHz through DC to 1,475MHz depending on mode, and impedance is 50ohms.
Kyocera will begin producing the filter at its Kagoshima plant in November at the rate of 2.5 million units a month, increasing to 5 million units a month in March 2004. The list price is under 30 cents in low production volumes.