Janine Love(01/14/2008 9:00 AM EST) - EE Times
The radio-frequency circuitry in mobile and portable devices remains some of the most resistant to integration. RF devices are very picky about who their neighbors are, and they sometimes find surprising ways to add interference to the signals they are responsible for handling. In the push for smaller footprints, the RF circuitry needs to shrink. The question is, what should be integrated, how, and how much?
There are competing strategies here: Integrate the power amplifier (PA) with the transceiver in a system-on-chip (SoC), leave it to stand alone, or combine it with the passive and control circuitry that is off-chip in a system-in-package (SiP). Which one is the winner? For applications requiring low output power and short ranges (think Bluetooth), the answer is SoC all the way. For applications requiring long range and high output power (think 802.11n WLAN connections), the best bet is to go with a SiP for the RF front-end circuitry (the PA, maybe the low-noise amplifier, matching circuitry, passives, switches, etc.). The standalone PA may be left out in the cold.
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