The past decade delivered an unprecedented and multifront evolution of TV broadcasts and receivers. These advances include stereo audio, HDTV, flat-screen technology using LCD and plasma displays, and TV receivers integrated into personal computers. The ultimate goal for TV receivers is a fully integrated solid-state TV with a flat-screen LCD or plasma display.

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While significant progress has been made toward this goal, tuners have fallen behind in the evolutionary development. This lag, however, is in the process of rapidly changing. Demand for smaller and lower-power televisions, flat-screen miniaturization, and even government standards are driving the development of silicon tuners to the razor's edge. In fact, the Federal Communications Commission (FCC) has set standards requiring all new televisions to incorporate digital tuners within the next two years.

Tuner history

The traditional tuner design for decades has been the “can” tuner, appropriately named because they are housed in metal enclosures to minimize RF interference and cross-talk. Despite the long history of use, can tuners have some major deficiencies.

First, the requisite use of tunable and fixed coils has virtually dictated discrete transistor designs for the tuner. This results in poor temperature characteristics and a physically large, power-hungry module — some as large as two inches by four inches. Perhaps the primary deficit with can tuners though is that each must be tuned individually as part of the manufacturing process. Not only is this a time-consuming step, the tolerance of the passive components results in a relatively broad acceptance standard for can tuner quality control.

As the disadvantages of the can tuner become more evident in today's modern devices, the silicon tuner is poised to unseat the can tuner in virtually all applications, in the same vein as transistors replaced vacuum tubes. Silicon tuners have the potential to offer a number of advantages and capabilities that the can tuner lacks.

Highly integrated silicon tuners are much easier to manufacture, and no tuning is required, reducing the overall cost of the tuner. The tuner can also be made extremely small compared to the can tuner because of the high level of integration.

Another notable advantage of silicon tuners is that a single tuner can receive TV signals using any of the several worldwide transmission standards. This means that an international manufacturer need only stock a single, meets-all-standards tuner, instead of one or multiple can tuners for each disparate standard.

Other advantages of silicon tuners include:

• integrated analog and digital tuners;
• multiple tuners in the same package for picture-in-picture and other applications;
• greater reliability;
• superior thermal stability;
• tighter quality control standards; and
• quicker channel lock: ~5 ms vs. ~150 ms.

These advantages, coupled with recent IC design rules and techniques have enabled practical silicon tuners. New IC techniques being used include enhanced BiCMOS processes, silicon-germanium (SiGe) transistors, and 0.18 µm design rules. This design evolution, when added with government dictates, will result in a rapid and universal transition to silicon tuners.