Analogs drive Sharp Aquos 45-inch HDTV

Figure 1: The TV's back panel gives a clue to the A/V complexity to be managed.

A big flat-screen HDTV may still be a big-ticket item for most consumers, but it is a virtual dreamland for analog semiconductor providers. As part of characterizing HDTV internals and BOM, one of our recent teardowns took the knife to Sharp's most current 45-inch LCD HDTVs—quite frankly a thing of beauty and an absolute shame to destroy.

The 45-inch-diagonal, $3,000-plus Aquos LC-45GD5U flat screen manages 1920 x 1080 resolution with an engine that's likely in line with the larger 57-inch and 65-inch models, which all support the same 1080p HDTV standard.

We'll focus here on the audio/visual (A/V) I/O and audio-processing board, which is home to much of the analog content. The TV's back panel (Figure 1) gives a clue to the A/V complexity to be managed. Cable inputs along with multiple base A/V interface standards are supported, including composite, component, VGA, S-Video, DVI and HDMI.

Sharp Aquos 45-inch HDTV (Click image to view teardown diagram)

Video processing takes place on other boards once the source signal has been selected and sent on its way, but the audio subsystem remains on the I/O board.

To create virtual Dolby surround sound, a pair of NJR DSPs combine with several D/A converters to perform enhancements to the switched audio inputs. Likewise, much of the front-end volume, equalization and subwoofer channel separation occurs in a Micronas device. Final audio amplification is via a Tripath TA2024 digital audio amp. Switching frequency content is filtered before delivery to the built-in speakers, with higher efficiency and lower-cost external components claimed as advantages.

A forest of high-current regulators and small-scale analog components covers the board shown here. The fragmented analog power and audio functions reflect an emphasis on design flexibility and speed.

This disintegration also reflects a fundamental difficulty in rolling up diverse analog content for a specific end product. The Sharp TV may be gone, but piecewise, analog design is probably here to stay.

- David Carey
President, Portelligent