1-GHz Cable-Box Tuner Satisfies HDTV, VOD Bandwidth Demands

The MT2121 single-chip TV tuner from Microtune pushes past the 860-MHz threshold by offering full 1-GHz bandwidth. With this tuning range, it's ready for new bandwidth-hungry consumer-electronics applications like HDTV, video-on-demand (VOD), and in-home media distribution. Wider bandwidth gives cable plants greater channel capacity, enabling more complex services and improved video performance.

Thanks to the tuner, cable-equipment manufacturers can deliver smaller, less expensive future-proof set-top boxes. Other potential applications include residential gateways, media entertainment servers, and digital cable-ready TV sets that comply with the FCC's new Plug and Play rules. The MT2121 dual-conversion analog-digital tuner fully complies with CableLabs OpenCable requirements, too.

All of its active components are on-chip, including a low-noise amplifier (LNA), mixers, and intermediate-frequency (IF) amplifiers. The first IF is 1220 MHz, while the second IF is in the 36- to 48-MHz range (usually 44 MHz). External surface-acoustic wave filters provide the selectivity. A portion of an input pre-selection filter improves performance in networks with severe differences in signal strength across the input band. An amplifier is optimized for the out-of-band forward data channel (FDC).

Fabricated in silicon germanium, the MT2121 comes in an 8- by 8-mm, 65-lead MicroLead Frame package (see the figure). Pricing is $5.50 in 10,000-unit quantities. Samples will be available this quarter, with production quantities to follow in the second half of the year. Reference designs are also available. An evaluation kit, due this quarter as well, is priced at $5000.