RF Transceivers from Analog Devices for Mobile WiMAX Applications

Building on ADI’s AD9352 and AD9353 family of integrated WiMAX transceivers introduced in 2006, the AD9354 and AD9355 consume less power than other transceivers in their class and are available in a 20 percent smaller package, while adding an additional receiver path for multiple-input multiple-output (MIMO) support. The power and space savings of the AD9354 and AD9355 enable manufacturers to incorporate WIMAX functionality into handsets, thumb drives or PCMCIA cards. By integrating ADCs, DACs and real-time control and calibration loops, the transceivers enable designers to eliminate all analogue and RF functionality from their baseband processors.

With separate digital and analogue blocks, the communications and applications processors can be manufactured in the most cost-effective digital CMOS process technologies, reducing power, package size and system design complexity.

“As a high bandwidth technology capable of reaching across several kilometres, WiMAX is proving to be an ideal communications medium for mobile devices,” said J. Pierre Lamoureux, vice president and chief technology officer for Wavesat Inc., a leading fabless semiconductor developer of WiMAX baseband chips and development tools. “Analog Devices recognised this potential early on. ADI’s design efforts and ‘smart partitioning’ of the analogue and digital blocks have yielded transceivers with the sensitivity and linearity that helps companies like Wavesat accelerate mobile WiMAX deployment.”

The AD9354 and AD9355 transceivers integrate two direct-conversion receivers that provide support for MIMO technology, which ensures mobile devices achieve uninterrupted WiMAX service. The direct-conversion transmitter architecture achieves state-of-the-art error vector magnitude (EVM), maximising network throughput. The transceivers communicate with a WiMAX terminal’s baseband ASIC or FPGA using the industry standard JESD207 digital interface that Analog Devices helped to define. The data bus requires 13 pins, which is comparable to competitive products employing analogue interfaces.

“By including on-chip data conversion and adding a second receiver signal chain to our transceiver architecture, Analog Devices is helping communications service providers extend WiMAX into the mobile marketplace,” said Thomas Gratzek, business director, WiMAX Transceiver Group, Analog Devices. “The AD9354 and AD9355 cover the key WiMAX frequency bands and are ideally suited for the small form factors in development.”

The AD9354 and AD9355 operate in the 2.3- to 2.7-GHz and the 3.3- to 3.7-GHz ranges and support channel bandwidths of 3.5, 4.375, 5, 7, 8.75 and 10 MHz. The devices have an excellent 3.25 dB noise figure (NF) and best-in-class linearity, both of which enable optimum real-world performance as WiMAX network traffic increases. The smart partitioning architecture enables autonomous AGC (automatic-gain control), transmit-power control (TPC), and calibration routines that dramatically reduce the RF driver development effort. Additionally, the highly accurate closed-loop power control enables 1-point factory calibration of transmit power. In contrast, other transceivers require 8 to 10 calibration points, which increase final test costs and extended development times.