Combining polar modulation techniques with its proprietary FullSpectra architecture and 0.18 micron silicon germanium (SiGe) BiCMOS process, fabless semiconductor supplier Sequoia Communications has readied a multimode transceiver chip that claims highest level of integration, lowest power consumption and the lightest phone level calibration burden. These advancements improve the battery life and reduce the footprint and the overall manufacturing costs of 3G handsets, stated Duncan Pilgrim, Sequoia’s director of product marketing. According to Pilgrim, the SEQ7400 is the industry’s first single-chip, polar transmit, seven-band, HEDGE (HSDPA/WCDMA and EDGE/GPRS/GSM) RF transceiver based on its patented FullSpectra architecture.

According to Brian Modoff, senior analyst and managing director at Deutsche Bank Securities, battery life, size and cost are primary obstacles to mass adoption of 3G technologies by consumers. “We estimate that the 3G handset market will reach 680 million WCDMA units in 2010, with HSPA accounting for 310 million of those units, and improvements in battery life, form factor and cost are critical to enabling this growth,” asserted Modoff.

As per Sequoia, polar modulation, the de facto standard transmit architecture in GSM/EDGE mobile devices, was successfully implemented for WCDMA in its first product, the SEQ5400. With the SEQ7400, the company is demonstrating working polar modulation in WCDMA/HSDPA. As a result, the company has established a clear path to large signal PA modulation in future products. Moreover, this architecture will enable a cost- and power-efficient means to integrate higher bandwidth standards, such as UTAN LTE, WiMAX and WiBro, in subsequent products, noted Pilgrim.

The product supports WCDMA, HSDPA, EDGE, GPRS, GSM modes across seven frequency bands simultaneously, making it applicable to major networks worldwide. The integrated receiver includes all LNAs and, unique to the SEQ7400, also eliminates the need for external WCDMA SAW filters. In addition, the low noise polar modulation transmit architecture eliminates the transmit SAW filters for GSM/EDGE, said the developer.

The integration of LNAs and filters significantly reduces the RF bill of materials (BOM) and board layout complexity creating a new benchmark in size and cost for all mobile devices using this product, said the manufacturer. “Lowering the overall cost of ownership and reducing the size of mobile handsets is critical for the broad adoption of 3G technologies,” said David Shepard, CEO of Sequoia Communications.

Complex calibrations and cumbersome programming interfaces have long plagued the RF transceiver market, making these devices difficult to integrate into a phone. Polar architectures have traditionally suffered from issues with calibrations. To address this, Sequoia Communications designed significant intelligence into the SEQ7400, making it a virtually self-calibrating device with a very simple programming interface. There is no burden placed on the baseband device or at the phone level. This will significantly reduce the factory calibration time for handset manufacturers, leading to much lower manufacturing cost and higher throughput.

The SEQ7400 comes in an 8 mm x 8 mm BGA package. Samples and complete RF evaluation boards are available now. Volume production is slated for the second half of the year. A 7 mm x 7 mm flip-chip version is also in the works and is expected to be released in summer. Pricing in volume is >$5.00. Meanwhile, efforts are underway to migrate to 90 nm RFCMOS using proven architectures.

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