Skyworks has announced a cost-effective CMOS front-end module (FEM) aimed at entry-level Class 12 GPRS handsets. The SKY77555 is a transmit and receive FEM based on CMOS PAs for dual-band cellular handsets that combine GSM900 and DCS1800 operation. Designed in a low profile and compact 5 x 6mm form factor, the FEM includes a complete transmit VCO-to-antenna and a receiver SAW filter. By eliminating the need to optimize matching between the amplifier and the switch, this module helps accelerate customers' time-to-market relative to other more traditional architectures, and simplifies the supply chain for high-volume, cost-sensitive phones.
The CMOS module consists of a GSM900/DCS1800 CMOS PA, Tx harmonics filtering, high linearity and low insertion loss PHEMT RF switches, and diplexer, and integrates a full dual-band GSM/GPRS power amplifier function. High accuracy power control and ramping is achieved via a closed loop power control system, which limits current drain under load mismatch conditions. The output of the CMOS PA die and the outputs to the two receive pads are connected to the antenna pad via PHEMT RF switches and a diplexer. The CMOS die, PHEMT die, and passive components are mounted on a multi-layer laminate substrate, and the assembly is encapsulated with plastic overmould.
"Skyworks' CMOS and GaAs front-end modules allow handset manufacturers to create ultra-small and low-cost GSM/GPRS solutions, as well as to select different price versus performance options from the same basic phone design," said Gregory L Waters, Skyworks' executive vice president and general manager for front-end solutions. "Our technology-agnostic approach provides our customers with a unique advantage in meeting their platform, geographic and cost needs. Looking ahead, we will continue to leverage both silicon and GaAs technology across a variety of new products, ranging from entry-phone devices to industry-leading, low-cost smart phones and 3G/4G solutions."
