Mobile audio IC is mainly applied to mobile phone and MP3 players. Handset audio IC can be classified into melody IC, CODEC and audio power system IC; MP3 system IC often refers to MP3 decoding IC and CODEC.

Seldom adopted in global leading handset manufacturers i.e. Nokia, MOTO, Sony Ericsson or Benq-Siemens, Melody IC seems to have a rather gloomy market. Especially after 2005, the above four manufacturers generally introduce application processor and custom analog baseband to get chord function. Major Melody IC clients are Samsung, LG and some Chinese manufacturers, most of which appear a gradually declining market share. Take Samsung for example, its market share has decreased by almost 10%. Also Chinese manufacturers are performing so awkwardly that even the sales volume of "black market handsets" is decreasing. Along with the development of semiconductor techniques, it will be much easier to integrate mixed signal to logic chips by pure CMOS techniques. Integrated chord SoC will become the main trend of the future. More and more melody IC suppliers appear in the market these years. Yamaha is the first in this field and for a time is the exclusive leading supplier. Later, its market is half-shared by OKI and then Vimicro rises suddenly. Fangtek is also striving to share in this field. The dramatically decreasing price of melody IC leads to a rather small profit margin, putting melody IC manufacturer into a dilemma. Yamaha, the only melody IC supplier of Samsung, also has to lower the price to maintain the bilateral business relationship. The profit of Yamaha metal semiconductor sector declines from 20 billion Yen in 2004 to 7.9 billion Yen now despite the big increase in shipments. OKI also suffers sharp decrease of 75% in its profit. Melody IC manufacturers have no choice but to change their business modes, yet which does not simply mean to add chord function to MP3 players because most basebands support MP3 Playing. In stead, melody IC manufacturers should develop towards the multimedia application processor field.
 
Only a few Audio CODEC manufactures are available in the market, namely TI, AKM and Wolfson. With a strict and high threshold to the CODEC field, only few manufacturers proficient in DELTA-SIGMA conversion can have a place in this field. What's more, audio CODEC is mostly likely to be applied with a great amount in compression music players especially MP3 players and digital cameras. In contrast, the application to handsets is only a by-line that may earn a little more but doesn't matter much if not. Audio CODEC also shares only a small market. It is unlikely that Nokia, MOTO, Sony Ericsson and Siemens take audio CODEC; they integrate audio CODEC function to baseband or application processor instead. Only Samsung, LG and Chinese manufacturers that lack custom baseband IC capability prefer to choose audio CODEC in handsets when sound quality is especially pursued, so the market demands of audio CODEC are even fewer than that of melody IC.

Now more and more independent audio system IC handsets can be found in the market. Before these audio systems were mostly integrated into analog baseband. Reasons listed below may contribute the appearance of independent audio system IC: Firstly, music handsets, MP4 handsets and TV handsets usually affix one or two small speakers for convenient browse or listen. Large output power is needed to drive these two speakers while the drive capacity of the audio systems integrated into baseband is usually not so good; however, shipments of this kind of handsets keep on increasing. Secondly, high sound quality handsets are launched into the market in large quantity, but the audio systems that are integrated into baseband are universally poor in sound quality. In 2005, about 75% of Nokia's handsets and about 70% of Samsung's handsets adopted independent audio system IC, while MOTO and Sony Ericsson much less.

Audio systems, especially Class-AB audio systems set an even higher threshold. National Semiconductor absolutely takes the unshakeable place of No.1 in the audio field; even strong powers like TI cannot compete with it. National Semiconductor thrives for thirty years in manufacturing handset audio systems and is extremely adept at controlling price performance. Its abundant product varieties extend to as many as 60 which can meet all kinds of demands and meanwhile offer a strong technological support.

Almost all other manufacturers avoid direct competition against National Semiconductor, who is considered as the superpower of class AB audio system field. They take products class D as their first choice instead, especially TI, trying to impact somehow on Notional Semiconductor by this means.

It is forecasted that products class-D will not take the mainstream in the next four or five years. Reasons are as follows: firstly, class-D has an advantage of higher efficiency£¬but this is not so distinct. i.e. class-D has a 15%-20% higher efficiency compared to class AB in terms of middle output power.

Secondly, audio amplifier system of class D generally has a higher price level than class AB. On average, the price of former is USD0.6-1.5. The less distortion, the higher price; While in contrast, the price of the latter is no more than USD0.5

The third is the poor sound quality, which is usually evaluated by the audience. Less distortion doesn't possibly mean high sound quality. Even though class-D can achieve the lowest distortion yet can not compete with class-AB on sound quality. That is because class-D generates a large amount of high frequency harmonic wave, which can not be heard by human beings in principle but inevitably affects our hearing, making the sound less popular.  

The last is the electromagnetic interference. The high frequency harmonic wave from the class-D may influence part of the handset RF or the antenna thus lowers the sensitivity to signals even makes them unable to work. The above mentioned problems may be easily settled except for the third one, which is almost fatal.    

Characteristics of common handset audio amplifier system, class-D

2. Handset Audio IC Manufacturers
2.1 Fangtek
2.2 Medeli Microelectronics
2.3 Yamaha
2.4 OKI
2.5 NEC
2.6 ROHM
2.7 Wolfson Microelectronics
2.8 AKM
2.9 TI
2.10 Vimicro
2.11 Winbond

3. MP3 Player Audio IC Market
3.1 The Global MP3 Player Market
3.2 China's MP3 Player Market
3.3 MP3 Player IC Market and Industry

4. Leading MP3 Decoding Chip Manufacturers
4.1 Actions
4.2 Sigmatel
4.3 PortalPlayer
4.4 Telechips
4.5 Fuzhou Rockchip Electronics
4.6 Atmel
4.7 ETO
4.8 T-square Electronics
4.9 Sunplus
4.10 AtChip
4.11 MosArt
4.12 Philips

5. Mobile Audio System IC
5.1 Mobile Audio System IC Market
5.2 Mobile Audio System IC Industry
5.3 Brief Introduction to Class-D Audio Systems
5.4 Shortcomings of Class-D Audio Systems and the Solutions 
5.4.1 Electromagnetic Interference (EMI)
5.4.2 Distortion Improvement
5.4.3 Improving the Frequency Response Range and Incidental Distortion
5.4.4 Strong Inductance and Capacitance of LPF at the Output Port
5.4.5 High Requirement on Power Supply 
5.5 Cases of Handset Audio System IC

6. Mobile Audio System IC Manufacturers
6.1 Yamaha
6.2 TI
6.3 National Semiconductor
6.4 Maxim
6.5 ON Semiconductor
6.6 Analog Devices