SAN MATEO, Calif. " Broadcom Corp. (Irvine, Calif.) significantly widened their address to the market for set-top box and TV electronics today with the introduction of two new chips: the BCM3405 multi-channel low-noise amplifier (LNA) and BCM3418 analog cable tuner.
Products of cooperation between Broadcom's Cable Modem product group and the company's internal high-frequency analog design group, the two chips will allow Broadcom for the first time to sell front-end electronics into cable-attached systems meeting analog or OpenCable requirements.
The company has a couple of years experience with tuners designed for QAM cable systems, explained director of marketing Jay Kirchoff. But where a good QAM system may require -82 dBC phase noise and -52 dBC distortion, the requirements for the CableLabs Open Cable specification are considerably more stringent. The new chips are designed to meet the new figures.
An additional design consideration is the gradual drift of high-end home entertainment products away from the one-cable, one-picture notion, according to Kirchoff. Modern feature-rich TV sets offer picture-in-picture, and are increasingly being driven toward cable-ready integration. And set-top boxes are evolving toward media gateways that support previewing, viewing and recording of multiple channels simultaneously.
All of this requires multiple tuners, and multi-channel LNAs to feed them. Hence the 3405 supports three in-band, one out-of-band and one bypass channel. This level of integration required careful attention to IM distortion and signal integrity issues, Kirchoff said, but it can result in considerable parts and cost reduction on the circuit board of either a cable-ready receiver or a set-top box.
Both chips are available now. The BCM3405 is $10 each in 10,000-piece quantities, and the BCM3418 is $5 each in 25,000-piece quantities. Both devices use 48-pin TQFP packages.