ADI's 2nd-generation chipset for advanced multimedia mobile handsets based on the 3G TD-SCDMA Interface

Analog Devices became the first company to offer a complete TD-SCDMA chipset from a single supplier and the company’s SoftFone chipsets have been an integral part of network trials held by wireless operators in China over the past three years, most recently achieving dual-mode operation and completing file transfers on a 384 kbps data connection with its SoftFone-LCR+ chipset. In addition, Analog Devices and its SoftFone-LCR chipsets have achieved successful market adoption, as evidenced by design wins with leading 3G TD-SCDMA handset manufacturers, including ZTE Corporation, Holley Communications and Inventec, along with leading Chinese mobile phone design houses, including Longcheer and Simcom.



The TD-SCDMA (Time-Division – Synchronous Code-Division Multiple Access) standard was proposed by the China Wireless Telecommunication Standards group (CWTS) and approved by the 3GPP (3rd Generation Partnership Project) as the low-chip-rate TDD standard of the 3G standard family. Designed for 1.6 MHz channels, it is compatible with 5 MHz unpaired 3G bands in any region of the world. TD-SCDMA can serve as a complement to W-CDMA deployments since it uses the same network backbone. Trial TD-SCDMA networks and 3G services are now established in various cities in China and based on recent reports, the TD-SCDMA network will grow within five years to over 40 million subscribers. Datang Mobile Analog Devices has been working closely with Datang Mobile, a leading company dedicated to the research and development of TD-SCDMA and the software provider for the SoftFone-LCR chipsets, and together the companies offer a series of solutions, which provide all the necessary hardware and software to develop a 3G TD-SCDMA phone suitable for volume production. In addition, the dual-mode TD-SCDMA software is provided by Datang Mobile and includes GPRS protocol stack software from Sasken Communication Technologies Ltd.



With the addition of the SoftFone-LCR+ chipset to its 3G product portfolio, TD-SCDMA handset manufacturers have the option to choose between a single platform for either voice-centric or cutting-edge multimedia capable handsets. The SoftFone-LCR+ chipset provides support for enhanced multimedia functions such as 3 megapixel cameras, USB, multi-format audio encode/decode, as well as advanced video capture and playback, and stereo audio codecs. The chipset supports video algorithms such as MPEG4, H.263 and H.264 for screen sizes up to QVGA; stereo audio codecs including MP3, AAC+, WMA and others; and it offers 128-voice MIDI ringtones – all handled in software. The chipset also supports full “boot from NAND” capability, so that cost-effective NOR-less designs for feature phones are possible. The chipset enables dual-mode TD-SCDMA/GPRS operation and achieves full 384 kbps 3G performance, enabling faster download speeds, video streaming, video telephony and Web browsing capabilities—critical requirements in supporting the migration to 3G wireless networks in China. In addition, the SoftFone-LCR+ chipset features the industry’s highest performance RF transceiver, Othello®-W, which offers the lowest call drop rates and best sensitivity available.



“Today’s announcement of our second-generation SoftFone-LCR chipset strengthens our technology offering and clearly demonstrates Analog Devices’ commitment to accelerating the development of TD-SCDMA technology,” said Christian Kermarrec, vice president, RF and wireless systems, Analog Devices, Inc. “As China migrates to 3G networks, our expanded technology offering is well positioned to address the wide-ranging needs of carriers and handset manufacturers – some of whom will choose to transition existing customers, focusing on voice-centric features, while others will immediately target the high-end of the market with advanced audio and video capabilities. The performance and functionality of the SoftFone-LCR+ chipset ensures that users will be able to have a multimedia-rich 3G experience on the new networks”



According to Michael Thelander, CEO of Signals Research Group, LLC, “Analog Devices’ expanded portfolio of TD-SCDMA silicon solutions is a positive indicator for both the company and for the continued development of TD-SCDMA as a wireless standard that can support a wide range of applications and end users. As TD-SCDMA trials move into the next phase toward full commercialization, this announcement is another indicator that ADI is well-positioned to benefit from the ramp of the burgeoning 3G standard.”



The SoftFone-LCR+ chipset supports all the critical functions required to build a TD-SCDMA handset, including the baseband signal processing and control, analog-interface functions and radio. It is based on the popular RAM-based SoftFone architecture also used in Analog Devices’ GSM/GPRS, EDGE and W-CDMA chipsets. ADI’s SoftFone-LCR+ dual-mode chipset consists of five chips, including the AD6903 digital baseband processor that utilizes the company’s Blackfin Processor achieving 260 MHz along with an ARM9 microcontroller, to perform both the communications and audio/video signal processing tasks in a media-rich handset. The software-based approach of the SoftFone architecture enables terminal developers to maintain maximum software flexibility. Additionally, the SoftFone-LCR+’s AD6857 Stratos-T analog baseband and power management IC provides a full set of audio features, as well as efficient power management. The SoftFone-LCR+ chipset includes interfaces for cameras, color displays, IR, USB and SD/MMC, allowing handset manufacturers to create several designs with varying levels of feature sets for a wide range of phone models.



In addition, the SoftFone-LCR+ chipset includes the Othello-W direct-conversion radio transceiver, offering solid performance and flexibility for either LCR time division duplex (TDD) or W-CDMA frequency division duplex (FDD) terminals. For dual-mode operation, the chipset adds the award-winning Othello-G transceiver, which enables the world’s smallest GSM/GPRS radio.