As the market for worldwide interoperability for microwave access or WiMAX continues to surge, chip suppliers continue to improve their wares and offer solutions that further streamline the design, simplify the test, cut the size and lower the cost. Consequently, several major suppliers were flaunting their latest chips at this week’s WiMAX world in Chicago, IL. Analog Devices, Inc. was among them, showing a second-generation RF-to-digital baseband transceiver to enable the IEEE 802.16d/e mobile WiMAX-based mobile communications devices, such as cell phones, personal digital assistants (PDAs), and handheld multimedia devices.

Building on integrated WiMAX transceivers introduced last year, the AD9354 and AD9355 consume less power and come in a 20% 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 analog and RF functionality from their baseband processors, said ADI.

“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, Analog Devices. “The AD9354 and AD9355 cover the key WiMAX frequency bands and are ideally suited for the small form factors in development.”

With separate digital and analog 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, added Gratzek.

Using 0.18 µm CMOS, 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), maximizing network throughput. The transceivers communicate with a WiMAX terminal’s baseband ASIC or FPGA using the industry standard JESD207 digital interface that ADI helped to define, according to the supplier. The data bus requires 13 pins, which is comparable to competitive products employing analog interfaces. Plus, on-chip LDO regulators simplify power management.

The devices 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. Plus, they offer 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, 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.

According to ADI, AD9354 and AD9355 mobile WiMAX transceivers are sampling now and are priced at $11.45 per unit in sample quantities. The AD9354 and AD9355 are housed in an 8 mm × 8 mm, 64-lead LFCSP packages. According to ADI, an evaluation kit, priced at $125.00, will be made available to qualified customers.

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