Nikkei Electronics Asia -- June 2009
Analysis
[Feature] Expanded Use of Silicon Tuners Transforms TVs

With analog television broadcasting slated for the axe in about two years in Japan, TV broadcast tuners are evolving rapidly, replacing old radio frequency (RF) analog circuits with new integrated circuits (IC) called silicon tuners. Signal demodulators are evolving with them, and by tracing the direction of their evolution it is possible to delineate the shape of tomorrow's TV.

In Feb 2009 Sony Corp announced that new mid-range and high-end TVs for the Japanese home market would come with silicon tuners developed in-house, rather than conventional tuner circuits (Fig 1). In fact, new models released by Sony from January of the same year were shipped with silicon tuners. The Eco BRAVIA Series, first exhibited at
2009 International Consumer Electronics Show (CES) for household appliances held in the US in Jan 2009 and released in Japan in February that year, also mounted silicon tuners. One reason behind the adoption of the silicon tuner module is its low power consumption, 1.6W typ. A source at Sony explains this is 35% lower than the prior module. 

At the 2009 International CES, LG Electronics Inc of Korea also disclosed plans to use silicon tuners in its major TV models. The result is that the two leading TV manufacturers in the world today announced the full-scale adoption of silicon tuners almost simultaneously.

Until now, the RF analog circuits in TV tuners were almost always composed of discrete components. In many fields of radio communication, it has become commonplace to single-chip RF analog transceiver circuits using complementary metal-oxide semiconductor (CMOS) technology, but the use of ICs lagged in televisions.

The first silicon tuners appeared for TVs in about 1999, and are already being utilized in applications such as cable TV set-top boxes (STB), personal computer (PC) digital broadcasting receivers, and Integrated Services Digital Broadcasting - Terrestrial (ISDB-T) one-segment receivers. Until now, though, large-screen sets for the home, the most common type, haven't used silicon tuners at all.

Now that silicon tuner performance is improving, the situation is beginning to change, and development of broadcast demodulator chips is getting more active, too. Development is polarizing: multi-function designs supporting high-speed mobile use, such as for automotive tuners, and low-cost designs for inexpensive tuners. This trend is likely to stimulate major diversification in TVs, leading to multi-picture TVs, automotive TVs, TV imagery in household appliances that have never offered such a function in the past, and full-segment broadcasting* on mobile phones, to name a few.

* Full-segment broadcasting: All 13 segments of the ISDB-T terrestrial digital broadcasting scheme used in Japan, Brazil and elsewhere.

Analog Support Essential

Silicon tuners have been on the back burner until now because, until recently, they were unable to compete with discrete tuners in terms of either performance or price.

Key performance issues included signal distortion, handling excessive received signal strength*, and poor analog reception, and it was difficult to reproduce the high Q of the discrete tuner's air-core coil in the silicon tuner. For most televisions, support for analog reception was viewed as essential for the time being. A source at Sony explains, "Even after analog broadcasting ends in July 2011, many cable TV service operators will continue to convert digital signals into analog and distribute them to their customers. Overseas, many regions will continue to use analog broadcasting." 

* Excessive received signal strength: Extremely strong received signals, such as when the receiver is near the broadcasting tower.

With a small production volume, silicon tuners faced problems competing with the low cost of discrete tuners, even though they were using older technology. Discrete tuner modules started at Yen200. A source at one silicon tuner manufacturer recalls, "Set manufacturers were asking if we couldn't provide silicon tuners at Yen60 or Yen70 apiece. It was simply impossible."

Costs to Drop around 2011

There are three major reasons why silicon tuners have suddenly begun showing up in large-screen home-use TVs: (1) the price of "CAN" type modules using discrete tuners has just about hit rock bottom, (2) the performance of silicon tuners has improved somewhat, and (3) the key characteristics of silicon tuners - small, thin and low-power - match the key sales points of TVs.

As far as price (1) is concerned, silicon tuners still have to cost less; they are still more expensive than discrete tuners.

One module manufacturer points out, "Sony's silicon tuner ICs are still too pricey for us to use." Sony itself made the decision to use the ICs in its own TVs because, according to a source at the firm, "Volume production would bring the price down," indicating that the firm's strategy is based on an assumption the costs will drop. Many other module manufacturers agree that the full-fledged transition to silicon tuners will happen in 2010 or 2011. According to companies like Alps Electric Co Ltd of Japan, Mitsumi Electric Co Ltd of Japan and Panasonic Electronic Devices Co Ltd of Japan, "Volume production of silicon tuners will increase in about 2011, when analog broadcasting ends, and costs will drop to match those of discrete tuners."

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