Cellphone chipset eliminates need for co-processor

Analog Devices Inc. (ADI) announced the availability of a new multimedia baseband processor with audio and video functions in EDGE and GSM/GPRS cellphones. The SoftFone chipset consists of the AD6900 digital baseband processor and the AD6855 analog baseband processor, which has capabilities such as 3Megapixel (MP) camera support, USB on-the-go (OTG), 128-voice MIDI ringtones and full-duplex speakerphone capability, without requiring a separate applications co-processor. The chipset is based on the company's RAM-based SoftFone architecture.

The AD6900 (LeMans) processor utilizes the Blackfin processor and ARM926EJ-S, both running at 260MHz to perform both the communications and A/V signal processing tasks. ADI explained that the capabilities of the Blackfin processor enable the multimedia video processing to be performed without the use of a co-processor.

The AD6900 can support video algorithms such as MPEG-4, H.263 and H.264 for screen sizes up to QVGA. The product also supports stereo audio codecs, including MP3, AAC+ and WMA, and offers 128-voice MIDI ringtones, which are handled in software. The processor includes built-in support for up to 3MP resolution cameras. For the transfer and uploading of pictures and music, or access to external storage and printing capabilities, the AD6900 supports USB OTG, whereby the handset can act as a host or client device. The AD6900 provides "boot-from-NAND" capability, and has been validated for compatibility with flash memory devices, including the recently announced M18 series from Intel and OneNAND from Samsung.

The companion AD6855 IC (Stratos-S) handles the analog processing requirements of the SoftFone chipset. The AD6855 provides analog and power management functions, including baseband radio interface, voiceband and stereo D/A conversion, and voltage regulation. The power management feature included in the SoftFone multimedia chipset controls the frequency and core voltage of the processor depending on the processing power being utilized. The analog audio subsystem supports multiple sampling rates of stereo audio for music playback, as well as concurrent audio streams and full-duplex speakerphone operation with more than 25 percent increase in output volume.

Analog Devices offers a choice of its Othello transceivers for use with the SoftFone chipset. The AD6546 Othello-E transceiver uses a closed-loop polar modulation transmitter and direct conversion receiver for EDGE/GPRS networks, while the AD6548 Othello-G transceiver supports GPRS operation.

The SoftFone AD6900/AD6855 SoftFone multimedia baseband chipset is currently available.