hf/rf ZONE Products for the week of September 22, 2003
TelASIC Says . . .
TC4000: Chipset Enables Universal Wireless Base Stations
World's first cost-effective wideband radio chipset to support
all major cellular air interface standards
TelASIC Communications announced the BaseFlex chipset, the world's first cost-effective wideband radio chipset to support all major cellular air interface standards, including GSM, GPRS, EDGE, IS-95 CDMA, WCDMA, cdma2000, and North American TDMA. The heart of the BaseFlex chipset is the company's high-performance data converter technology, which reduces up- and down-conversion to a single stage, simplifying RF front-end complexity. The chipset delivers instantaneous bandwidth sufficient to cover any licensed commercial radio band up to 75MHz, enabling a powerful wideband radio architecture that can process multiple 2G, 2.5G, 3G and future wireless standards at the same time, within the same footprint as today's single-carrier, narrowband architectures. A multi-channel, fully programmable digital tuner completes the chipset.
Tony Giraudo, president and CEO of TelASIC explained, "The BaseFlex chipset embodies the unique value proposition that TelASIC brings to developers of base station hardware. The combination of data converters and our fully programmable tuner delivers the wideband radio architecture that allows base station designers to build a truly universal base station platform that produces both immediate and long-term product portfolio benefits."
The key features of the BaseFlex chipset are:
Developers of wireless base stations that use the BaseFlex chipset will reap wide-reaching benefits associated with a common wideband hardware platform:
The BaseFlex architecture complements industry organizations that support open radio interfaces, including the Common Public Radio Interface (CPRI), which aims to define a publicly available specification for the key internal interface of radio base stations, and the Open Base Station Architecture Interface (OBSAI - www.obsai.org), which focuses on open specifications for certain parts of the base station's internal architecture and key interfaces.
"Base station manufacturers are under intense pressure to not only keep cost down, but also support an ever-expanding number of air-interface technologies," observed Allen Nogee, principal analyst in wireless technology at In-Stat/MDR. "By employing a common hardware platform, such as that enabled by TelASIC's BaseFlex chipset, manufacturers gain the flexibility to support multiple air standards while still simplifying their designs."
The chipset consists of the TC1410, a 14-bit, 240 MSPS analog-to-digital converter, the TC4000, a multi-channel programmable tuner, and the TC2400, a 14-bit, 480 MSPS digital-to-analog converter. TelASIC's integrated circuits are implemented in IBM's SiGE Bi-CMOS and CMOS process technologies, which contribute to the excellent performance characteristics of each chip in the chipset.
"IBM's SiGe process technology can be of tremendous benefit for
high performance data converter integrated circuits like TelASIC's,"
said Michael Concannon, vice president, Foundry Services, IBM Microelectronics
Division. "We understand that companies like TelASIC need to get to
market as quickly as possible, with the latest technologies, and working
with us allows them to keep their focus on customers and products, while
we focus on manufacturing."
analogZONE Says . . .
TelASIC is one of the spin-offs created by MILCOM using IP from a defense company, and the first where that IP has come from the Raytheon stable. Despite the 2001 launch -- which analogZONE itself recognizes was an inauspicious year for a company birth -- TelASIC raised $22.5 M in its first round of funding. Using patents from the Raytheon vault they launched high-speed ADCs and a high-speed DAC a few months ago. While analogZONE reviewed the last two parts, the TC1410 14-bit 240 Msample/s ADC and the TC2400 14-bit 480 Msample/s DAC, we were not aware of the big picture of where TelASIC intended to use them. Those reviews and the latest versions of the data sheets from the company are worth revisiting to see how the characterization of both has been bettered over the last months.
Those who have worked on defense-funded projects involving communications understand that some developments can be many years ahead of the commercial implementation. In this arena both TriQuint and SPT produced commercial high-speed conversion parts some 6 - 7 years ago, but they turned out to be too early for the market to be able to do anything with. TelASIC's timing is perfect. The company's designers are very familiar with IBM's 5HP and 7HP SiGe processes and the CU-11 CMOS process and have locked in to IBM for foundry services, with IBM taking an equity stake in TelASIC (similar to the arrangement with SiGe Semiconductor.) The company also boasts of 50 SiGe products designed and sold by the team, and that it has a recent IBM/Raytheon/DARPA contract.
The latest part, the TC4000, completes the product picture for an all-standards cellular base station providing the path from a single down-converted analog signal to a high-frequency analog output suitable for a single up-conversion to the final frequencies. The company is calling it a "tuner" which I guess is as good a title as any once you understand what it is doing.
The receive side has 8 fully-differential channels which can be set to any of the current standards, GSM, WCDMA, GPRS, EDGE, IS-95, and cdma2000, and can probably be used with any emerging standard that we can imagine at this moment. The channels can be fed from 2 separate ADCs (TC1410s, of course) allowing for band flexibility as well, and AGC is available for gain control in the receive chain to prevent over-powering. The remainder of the chain can be studied in the technical information available from TelASIC but it should be noted that the DDS frequency in each channel, filter coefficients and options for formatting the outputs are all programmable through a µP interface.
On the transmit side there are fully-differential 4 channels, roughly with the various blocks in reverse order from the receive side, which end up in a summing tree that can be fed to a single DAC (TC2400) for upconversion and power amplification. A very high linearity of a single PA would be critical in a wideband application and if the standards cannot be met there is an alternative where the channels can feed up to 4 separate DACs to make it easier. The DAC(s) is(are) also fed with a pseudorandom noise source that is filtered to provide a dithering signal that reduces the spur content on the analog output. This is normally set at about 5 MHz wide (around dc) but it can be shaped and scaled with a 128-tap FIR filter and can be interpolated to match the actual DAC clock using a CIC filter -- all programmable of course.
The TC4000 uses 1.6 V for the core and the I/Os can be powered from 1.4 V to 3.6 V for LVDS and CMOS. Power is quoted at less than 600 mW per transmit/receive channel.
The timing is, as we said, perfect for the market which is reeling in red ink and is not at all happy about updating equipment with yet more dedicated boxes that could be out-of-date within a few years. Here the hardware is the same whatever the standard, and whatever the frequency. It is also fully software-configurable so that standards can be implemented according to sector demand instead of having over-supply of some hardware and an inadequacy of other hardware -- a very familiar picture today. Designers in the cellular industry are very set in their own particular ways of doing things -- always a surprise in such a still-emerging industry -- but there will be no doubt that they will sit up and take notice of what TelASIC is doing here. The company is well-structured, well-funded and has a solid background on which to deliver its promises: I'm sure it will.
The TC4000 is in a 652-pin quad package and is not yet priced. Limited
samples and a demonstration are available from the company -- as is preliminary
technical information. With the complexity involved in this part I would
suspect that a full data sheet is not going to be available very quickly.