RF Synthesizer for 3G Cellular Handsets

The Si4133W is a completely integrated RF synthesizer for third-generation (3G) wireless communications. The device, a dual-band RF synthesizer, is capable of generating high-fidelity RF signals up to 2.5 GHz and integrates the entire solution in a monolithic CMOS chip. It is the latest addition to the company's family of RF synthesizers and meets the synthesizer performance requirements for Wideband Code Division Multiple Access (W-CDMA), one of the standards approved for use in 3G cellular systems. W-CDMA is capable of delivering data rates up to 2 Mbps, which is 10 times faster than current solutions, creating a new frontier for high-speed, data-rich wireless applications.

The device eliminates VCO modules and as many as 40 external discrete components. Featuring fast settling times, the signal output of the synthesizer stabilizes to an accuracy of 0.1 ppm in 200 microseconds -- meeting the compressed mode requirements of W-CDMA. The product performs RF synthesis in two bands (2.3 to 2.5 GHz and 750 MHz to 1.6 GHz), as well as IF synthesis from 62.5 MHz to 1.0 GHz. Based on the stable integer-N phase-locked loop (PLL) architecture, it also delivers consistent part-to-part operation.

The device's architecture integrates three PLLs in a single CMOS IC, which, depending on the configuration, can reduce board space by up to 85 percent over conventional solutions. It also shortens development cycles because all the prescaler, loop filter and divider settings are either automatically configured or programmed via software control.

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