Highly Integrated AM/FM Radio Receivers Build Up a Whole New Automotive Entertaining System
As the cars are evolving from pure transportation vehicles into stylish consumer’s products combined with the functions of recreation and entertainment, the consumers are asking for more on the car entertainment features. The automotive industry is facing significant market pressure to lower costs without sacrificing performance. This is especially true in entry-level automotive markets, where consumer demand for lower-priced vehicles drives annual growth at rates above 10 percent. Silicon Labs is making the most of its core competence to design a high-performance mixed signal CMOS chip, and puts focus on the huge, fast-growing automotive electronics and information entertainment area, in order to meet the demands of simple design and lower cost with its outstanding broadcast audio products in this field.
The automotive AM/FM radio receiver Si474x is a completely integrated entry-level middle band radio chip solution from Silicon Labs. In 2005, Silicon Labs had announced its first RF-to-Audio receiver chip, and the total shipment since then has reached over 200 million units so far. Silicon Labs is capable of integrating digital signals and RF into a single-on-chip architecture, which means the digital signal processor and RF can be integrated into on a single chip, thus the RF-to-audio integration can be implemented, that can significantly reduce the external component count to furthermore reduce the system cost.
Simplified Design Speeds Up the Time-to-market
The LNA, LDO, AFC, AGC, ADC, DSP, DAC and RDS feature modules are all highly integrated in the Si474x chip itself, which has eliminated the considerations for engineers of too many complicated external circuit design in the designing phase. It also eliminates the environmental influences like coupling and RF signals from too many external circuits. The Si474x is excelled by reducing the external component count and associated cost more than 40 percent compared to competitive solutions.
Figure1: Highly-integrated simplified design of Si474x
From figure 1, we can understand that the Si474x is highly integrated and the external component count is extremely low, thus there is no need for manually alignment like before. The single chip solution is packaged in a tiny 4 x 4 mm package, requiring a PCB footprint of less than 4 cm2 inclusive of all bill-of-materials. This level of integration minimizes routing of sensitive RF signals outside of the IC, further simplifying the PCB design process and reducing the manufacturing cost.
At the same time, the Si474x family can provide the receivers which can be used to build up a complete audio and data receiving systems. Completely integrated entry-level middle band radio chip solutions can be implemented inside this chip including FM, FM radio data system (RDS), AM, long wave (LW), short wave (SW) and weather bands. The Si474x family supports worldwide radio band requirements including 76MHz-90MHz in Japan and 87.5MHz-108MHz and other channels. Furthermore, the Si474x family can output analog audio signals and digital audio signals; it can be also used to record audio directly.
The automotive electronic devices are working in a special environment. The audio receiver is always interfered by outer environmental factors. That will lead to noise and signal attenuation and reduce the performance of components. The radio wave is always reflected by the buildings and tall trees, Si474 family will receive reflecting waves with different amplitudes and phases. To solve these problems, the Si474x family has embedded multiple-path signal suppressing functions in design. In figure 2, the Si474x internal DSP will detect and suppress the multi-path interferences, thus can eliminate the bad influences from multi-path interferences and improve the performance of the radio receiver at multiple-path conditions.
Figure 2: Si474x mitigation No mitigation
The in-car environment is much noisier due to the engine starting and the noises of other electronic devices (e.g. wind shield wipers and electronic windows) will have influence on the chip. Si474x family provides completely configured AM and FM noise suppressor to reduce the noise from outer environmental interference. The AM/FM noise suppressor improves the audio quality by setting the detecting threshold value, interval, speed, filtering bandwidth and delay.
In addition, the Si474x family has integrated the RDS (Receive Data System) decoder. The RDS decoder can transfer text contents like sports, traffic and other music/entertaining information to inside the Si474x chip through FM wave band. The RDS decoder then processes then decodes the data, then outputs to the main chip and displays on the screen. This is very useful and convenient for the consumers. All the aforementioned functions are automatically implemented inside the chip, the design engineers are able to control the chip by software configuration through very few interfaces. This can eliminate many manual operations and improve the automation level. Thanks to its highly integrated level, it has very high compatibility with hardware and software, and it is easy to transport to other platforms for software. Users can design and manufacture the products easily and gracefully, which can help achieve a quicker time-to-market.
The standards of automotive electronics industry are much stricter, and the Si474x family has excellent automotive-grade quality and performance and it is AEC-Q100 qualified. Silicon Labs has just received the ISO/TS-16949 qualification of international automotive industrial quality system standard certification.
The entry-level automotive radio market is growing fast; Silicon Labs has its expertise to satisfy any related needs from this market. Silicon Labs is making the most of its award-winning and patented CMOS digital architecture to reduce cost in such an important market. In the meantime, the performance is 100% guaranteed, and the expecting quality from the consumers is satisfied.
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