Wireless Systems Design

Quad-Band Power Amplifier Is Ultra Small

The smallest available quad-band power-amplifier (PA) module with integrated power-control circuitry has hit the market. As an extension of the PowerStar family of PA modules, the RF3133 product boasts the same power control based on collector control. In addition, the RF3133 PA features quad-band performance in a small, 7-×-10-mm leadless chip carrier footprint.

All PowerStar PA modules eliminate the need for directional couplers, detector diodes, power-control ASICs, and other power-control circuitry. At the same time, they provide handset manufacturers with benefits like reduced component count, improved production yield, simplified phone calibration, and faster time to market. RF3133, the third PowerStar product to be introduced, takes these capabilities one step further by offering improved integration and reduced internal component count. In fact, utilizing only 70 mm2 of board space, the RF3133 is considered to be the world's smallest PA module with integrated power control. This size was achieved by integrating critical passive components onto a gallium-arsenide heterojunction-bipolar-transistor (GaAs HBT) process technology.

The collector control method of power control utilized by RF3133 was developed to meet stringent European Telecom-munications Standards Institute (ETSI) specifications for transient spectrum and burst timing. Unlike other methods of power control, collector control requires no external components and demonstrates minimum variation across temperature, frequency, and voltage. Consequently, the RF3133 PowerStar PA module is able to provide handset customers with robust and consistent burst timing and transient spectrum performance. Both of these are primary specifications required by ETSI for cell-phone "full type approval" (FTA).

The RF3133 is designed for use as the final RF amplifier in single- and multiband GSM, DCS, and PCS handheld digital-cellular equipment. It also finds a home in applications in the 880-to-915-MHz, 1710-to-1785-MHz, and 1850-to-1910-MHz bands. It includes a fully integrated, silicon CMOS power-control loop that meets all spectrum and burst-timing requirements, with 50-ohm input and output terminals. It also includes software tools that allow the engineer to instantly calculate ramp profiles.

The multiband RF3133 is offered as part of the POLARIS TOTAL RADIO transceiver, which performs the transmit and receive functions of a wireless handset's radio section. Now available, it is manufactured using GaAs HBT for power amplification with silicon CMOS to integrate the power-control circuitry.

RF Micro Devices
7628 Thorndike Rd., Greensboro, NC 27409-9421; (336) 664-1233, FAX: (336) 931-7454, www.rfmd.com.

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