CMMB (China Mobile Multimedia Broadcasting) is China's first mobile TV standard with independent intellectual property rights, specifically designed for mobile devices. It is a portable multimedia broadcast service jointly developed by China Mobile and China Broadcasting Corporation, offering TV content to small-screen devices such as smartphones, PDAs, and in-vehicle TVs. As mobile phones have evolved into multifunctional devices capable of handling both communication and multimedia tasks, integrating CMMB has become a natural progression. The system employs a combination of satellite and terrestrial transmission methods, operating on the U-band (1.55–3.4 GHz) and S-band (470–860 MHz). Unlike traditional streaming services, CMMB does not incur data charges, making it a cost-effective and efficient solution for mobile TV. This unique feature has driven strong market demand for CMMB-enabled devices. In this paper, we introduce the IF228 chip, a dedicated CMMB receiver designed to enhance mobile multimedia broadcasting.
When selecting a CMMB chip, several key factors must be considered, including technical performance, integration level, power efficiency, and cost-effectiveness. The trend in the industry points toward highly integrated chips that combine tuner, demodulator, decoder, and conditional access functions into a single package. This approach reduces development complexity and lowers production costs, facilitating mass adoption. SIP-based solutions are known for their stability and compliance, making them a preferred choice. In the long term, all-in-one chips like the IF228 will dominate the market due to their compact size and superior performance.
The IF228 chip stands out for its high integration and ultra-small form factor. Built using a 65nm process, it comes in a TFBGA 5mm × 5mm package with 0.65mm ball pitch, making it the smallest CMMB demodulation chip available. Its compact design simplifies PCB layout and reduces overall system cost. The chip supports a 50mm² footprint, making it ideal for space-constrained applications.
In terms of performance, the IF228 delivers exceptional demodulation capabilities. It can handle speeds up to 800 km/h, making it suitable for high-speed vehicles like trains and even aircraft. It also performs well in urban environments with multi-path interference. Under standard TU6 conditions, the QPSK demodulation threshold is below 7.3 dB, while the QAM 16 mode can still demodulate at a 12.5 dB signal-to-noise ratio even when the two-path delay reaches 75μs. These specifications ensure seamless reception across various network scenarios.
The IF228 also excels in resisting single-frequency interference, a major challenge in broadband systems. It can successfully receive signals even when in-band interference exceeds the received signal by 15 dB. Moreover, it quickly recovers from strong interference without experiencing the "Schmitt effect," where reception only resumes after the interference weakens. This feature improves user experience in crowded electromagnetic environments and reduces EMI requirements on the PCB.
Power efficiency is another key advantage of the IF228. Using time-slot receiving technology, it consumes as little as 36 mW on average, with each time slot using less than 10 mW. In power-down mode, current consumption is extremely low, simplifying power management. The chip’s I/O voltage range (1.6–3.6 V) eliminates the need for additional voltage regulation, and its PWM output pin facilitates antenna integration.
Finally, the IF228 supports multiple clock frequencies, including 10, 12, 13, 18, 19.2, 20, 24, 26, 27, and 30 MHz. This flexibility allows it to share a crystal with the application processor and baseband chip, reducing component count and saving board space. Overall, the IF228 represents a significant advancement in CMMB technology, offering a reliable, efficient, and future-ready solution for mobile TV reception.
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