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Cable Technology Feature Article

November 11, 2010

MaxLinear's Cable TV Front-End Chip Cuts Power, Size of Cable Gateways

By Ashok Bindra, TMCnet Contributor

Many cable video set-top-box and emerging gateway designs feature up to four or even six dedicated video channels. These devices require a multiple tuner-demodulator (also called an MPEG tuner) ICs. Integrated RF and mixed-signal semiconductor supplier MaxLinear, Inc., has released a new cable TV front-end chip with dual tuners and dual QAM demodulators that cuts in half the number of tuners needed for multi-channel DOCSIS and cable video gateways.

The MxL251, with its integration of discrete ICs and expensive external discrete components on the PCB, along with significant size reductions can unleash new creativity in gateway design and price, said MaxLinear.

Developed in standard digital 65 nm digital CMOS process, the MxL251 is a single-die digital front-end chip with two narrow-band RF tuners (6 or 8 MHz), two quadrature amplitude modulation (QAM) demodulators and an integrated splitter to support dual- or triple tuner designs.

The device supports all global cable standards including ITU-T J.83 Annex A/B/C. The tuner can receive one RF coaxial cable input and delivers two MPEG transport stream outputs or two channels on an intermediate frequency (IF) output. The integration of discrete tuners, demodulators, external RF splitter and loop through elements significantly reduce PCB board size, external component costs, and vastly simplifies design, claimed the maker.

 The MxL251 is packaged in a compact 7mm x 7mm 48-pin QFN package and consumes 700 mW of power for the combined two channel reception mode, along with a battery operation mode of 350 mW. Thus, allowing manufacturers to provide only two battery cells for back-up instead of three or four cells with current implementations, explained MaxLinear.

In a statement, Kishore Seendripu, MaxLinear’s CEO, said, “The MxL251 once again shows the advantages of MaxLinear’s core wideband CMOS RF-mixed signal IC technology platform, which is ideally suited for developing the lowest power and smallest size RF-demodulator multiple-channel SoC solutions that deliver industry-leading functionality and performance.”

With its ultra-low power consumption, the MxL251 has no special heat dissipation requirements, which saves cost on fans, heat shields, heat sinks, etc. This also helps designers to meet the system power consumption levels needed to comply with the U.S. Energy Star code of conduct for both standby and operating modes.

Pin-compatible with the MxL261, a dual-tuner, quad demodulator digital cable front-end chip with the ability to capture eight channels in a 200 MHz input frequency bandwidth, the MxL251 is in sampling mode and will be generally available in the second quarter of 2011, said MaxLinear.

Ashok Bindra is a veteran writer and editor with more than 25 years of editorial experience covering RF/wireless technologies, semiconductors and power electronics. To read more of his articles, please visit his columnist page.

Edited by Tammy Wolf