At this month's 3G World Congress & Exhibition in Hong Kong, Analog Devices Inc. disclosed a single-chip radio transceiver for the enhanced data rates for GSM evolution (EDGE) cellular standard. Exploiting its direct-conversion Othello radio architecture, the new Othello-E transceiver integrates virtually all the necessary components, including voltage-controlled oscillators (VCOs), PLL loop filters and power management, for a complete quad-band EDGE radio design. Additionally, it comes in an ultrasmall package. The device can operate in the 850 MHz, 900 MHz, 1800 MHz and 1900 MHz frequency bands, enabling worldwide coverage.

To achieve the increased linearity necessary for the signals that support EDGE data rates, the Othello-E radio leverages a high-performance logarithmic RF power detector to enable a closed-loop polar modulation transmitter design, which also contributes to better manufacturability and reduced design complexity. Closed-loop polar modulation is an improvement over open-loop polar designs, which require close matching of the transceiver and power amplifier.

“We have experienced great success with our SoftFone EDGE baseband processors over the past two years and we are excited to now offer our EDGE customers the benefits of our innovative Othello radio architecture in a single-chip solution,” said Christian Kermarrec, vice president, RF and wireless systems, Analog Devices Inc. (ADI). “There is renewed interest for EDGE throughout the world as a low-cost upgrade to existing 2G networks, and as a reliable, high-speed fallback technology for cellular operators that are launching 3G networks.”

According to data from the global mobile suppliers association (GSA), 116 GSM/EDGE networks have launched commercial services in 70 countries. The GSA also found that 169 operators in 91 countries have committed to EDGE deployments. Illustrating the role of EDGE as a complementary technology to 3G networks, the GSA found that there are 55 operators deploying EDGE and WCDMA, with 23 combined networks in commercial service.

The Othello-E transceiver (part number AD6546) is a single-chip solution combining all the radio and power management functions for an ultracompact, cost-effective EDGE radio. It includes separate low-noise amplifiers (LNA) for all four GSM bands (850 MHz, 900 MHz, 1800 MHz and 1900 MHz) and a fractional-N PLL synthesizer with integrated VCO and loop filter for local oscillator (LO) generation. An on-chip high-accuracy logarithmic power detector enables the closed-loop polar modulation, and ensures compatibility with power amplifiers from multiple suppliers while maintaining loop stability. In addition, the closed-loop architecture maintains stable, reliable, spec-compliant performance regardless of variations in PA characteristics due to manufacturing process variations, component aging, temperature or frequency. On-chip voltage regulators enable direct connection to the battery supply, eliminating the external regulators needed by other transceivers and reducing BOM component count and PC board area.

The Othello-E radio also complements Analog Devices' family of SoftFone baseband chipsets for EDGE wireless terminals. ADI's SoftFone chipsets are RAM-based, thereby providing handset manufacturers with the flexibility to support changes in cellular standards and/or customize features and options for a wide range of phones by simply changing software without the need to add new hardware. Together, SoftFone and Othello enable substantial BOM savings while maintaining flexibility, providing benefits to handset manufacturers and operators.

The Othello-E radio is sampling now.

For more information, visit www.analog.com