Power Amplifier Integrates Full Quad-Band GSM/GPRS Functionality

Dec 2, 2008 2:55 PM, MD&D News Staff

The AX508 power amplifier (PA) from Axiom Microdevices integrates full quad-band GSM/GPRS Class 12 functionality on a single IC using mainstream silicon CMOS process technology. According to the company, it offers improved performance compared to the AX502 as well as a smaller footprint, using a 5- by 3.5- by 0.9-mm low-profile micro-leadframe package (MLFP).

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Axiom developed its CMOS PAs using its patented Distributive Active Transformer (DAT) technology, which makes it possible to use 0.13-µm silicon CMOS process technology to integrate all of the functions between the transmitter output and the transmit/receive switch. The technology also enables power gain stages, small signal control circuitry, and 50-Ω input and output matching circuitry on a single die.

Furthermore, DAT enables a direct connection to the transceiver output and the transmit/receive switch input without the use of the external matching components. This helps designers achieve what was previously only viable with devices manufactured in proprietary gallium-arsenide (GaAs) process technology and assembled in complex multichip-module packaging.

The AX508 amplifies low-level radio-frequency (RF) signals to the required high-power levels needed for transmission in GSM/GPRS mobile phone handsets or data modules. It supports full quad-band (GSM 850/900/1800/1900) operation. Power supply ranges from 2.9 to 5.5 V, and RF input ranges from –2 to 8 dBm. The device also offers extended range for low-power-mode operation.

A fully integrated closed-loop power controller ensures that the GSM power/time mask and switching spectrum may be met with adequate margin for robust mass production when subjected to a real-world cell-phone environment, such as highly elevated voltage standing-wave ratio (VSWR) and low supply voltage.