Comparison of CMMB terminal chips: Analysis and evaluation of several typical tuners

CMMB terminal chips contain tuners, demodulators, decoding and descrambling modules, and the tuner at the front end is crucial. This article selects five typical tuner chips for analysis and comparison, namely ADMTV102, ADMTV803, MxL5007T, SMS1180 and TP3021.

ADMTV102 is the earliest tuner launched by ADI that supports the CMMB standard. It has been widely used in domestic terminal devices such as mobile phones, mobile TVs, MP4s, etc. In addition to supporting CMMB, the chip also supports national standard DTMB, European DVB-H/T, T-DMB launched by South Korea, and FM. The receiving bands include FM (65~108MHZ), band-III (174~245MHZ), VHF (470MHz~862MHz), and L-band (1450~1492MHz).

ADI's recently launched ADMTV803 also supports multiple digital TV standards, and the receiving bands are VHF (54~245MHz) and UHF (470~862MHz). Data from ADI's official website shows that ADMTV803 has newly added support for the US ATSC-M/H and Japanese ISDB-T standards, and has switched from FM to support FM-upgraded DAB. Through disassembly, it was found that the chip's RF signal input pins were reduced from three in ADMTV102 to two, and the system module layout is highly similar to ADMTV102.

The MxL5007T is special in that it can receive signals in the continuous frequency band from 44HZ to 885MHz, supporting almost all major cable TV, terrestrial digital and analog TV standards. The chip was put into mass production by Maxlinear in the second quarter of 2008.

SMS1180 is the first SIP packaged chip containing a tuner and demodulator launched by SIANO for the Chinese market in July 2008. In addition to supporting the UHF (470~862 MHz) band, the tuner also supports the S band.

TP3021 integrates a tuner, demodulator, crystal oscillator and passive devices in a 7x11mm2 module. It is an integrated CMMB receiver that was mass-produced in November 2008 by domestic manufacturers Taihe Zhiheng and Sharp. It supports the UHF and S bands of the CMMB standard, but its official website does not disclose whether the built-in tuner also supports other digital TV standards.

Based on the information listed above, we can see some development changes in CMMB terminal chips, from the early tuner, demodulator, and decoder each on a single chip to the current more mainstream tuner and demodulator combined into one, and the supported CMMB bands are also increasing.

Chip size

The chip size of ADMTV102 is about 2.82x2.87mm2. Based on the same feature size, the area of ​​ADMTV803 is only 64% of ADMTV102, which is 2.26x2.29mm2. The chip size of MxL5007T is 2.70x2.70mm2, which is not obvious in the current tuner, but it has certain cost advantages compared with the tuner chip area of ​​4.81x3.51mm2 in SMS1180. The tuner chip size of TP3021 is 2.75x2.69mm2.

Power consumption

The power consumption of ADMTV102 when receiving VHF and UHF signals is 180 mW and 200 mW respectively, while the power consumption of ADMTV803 is only half of that of ADMTV102, and the low power consumption in continuous mode is 92 mW (VHF) and 94 mW (UHF) respectively. Shengjing (Shanghai) Microelectronics Co., Ltd. (hereinafter referred to as "Shengjing") analyzed the RF signal receiving path of the chip and found that the circuits of the two chips from low noise amplifier to filter are quite different; the power consumption of MxL5007T is the highest among the five chips, at 300 mW, making it more suitable for set-top boxes than mobile devices; the power consumption of TP3021 is less than 80 mW, and SIANO claims that the power consumption of SMS1180 is very low, at only 31 mW.

Sensitivity

The typical dynamic range of the automatic gain control of ADMTV102 is -102dBm to 0dBm, and that of ADMTV803 is -102dBm to +10dBm. The receiving sensitivity of TP3021 using QPSK modulation during testing is about -99.6dBm. The tuner and demodulator of SMS1180 each have a circuit module to ensure its receiving sensitivity in indoor depth environments. Shengjing will dissect the tuner chip in SMS1180 in the near future.

At present, more and more domestic and foreign companies are involved in the design and production of CMMB chips. For example, Lingxin Integrated has launched S202ITM and S203ITM; France's Dicom launched the Octopus platform and DIB10098 chip in February 2009. DIB10098 is a 65nm process chip integrating tuning, demodulation, memory and power management modules. In addition, Broadcom will also mass-produce CMMB chips integrating tuners and demodulators at the end of 2009. The chip consumes less power and can automatically identify and select frequency bands.

Figure 1: The actual proportion of the top layer of the package of five chips (from left to right are ADMTV102, ADMTV803, MxL5007T, SMS1180 and TP3021).

Multi-standard tuner MxL5007T

MxL5007T is a digital terrestrial silicon tuner that Maxlinear mass-produced in 2008. The chip is characterized by its ability to receive continuous frequency band signals from 44HZ to 885MHz through antenna or cable. It supports multiple standards such as China CMMB, US ATSC, ATSC-M/H, and Europe DVB-T.

From the chip layout module distribution diagram and system block diagram (Figure 2 and Figure 3) revealed by Shengjing, it can be seen that the MxL5007T integrates a variable gain LNA, a mixer, a low-pass filter, an automatic gain amplifier, a baseband DSP and a phase-locked loop, etc.

Figure 2: MxL5007T layout module distribution diagram.

Figure 3: MxL5007T chip system block diagram.

The MxL5007T chip size is 2.7X2.7mm2, which is medium-sized among digital TV silicon tuners, but compared with ADI's VHF/UHF multi-digital TV standard silicon tuner ADMTV803, the single chip has about 40% more area.

Through research, Shengjing found that the MxL5007T chip I2C interface and baseband DSP have about 110,000 gate units, accounting for 18% of the entire chip area. Compared with ADMTV803 (whose area only accounts for about 5% of the entire chip), the MxL5007T digital control logic is much larger.

In addition, the chip integrates two phase-locked loops. In addition to the phase-locked loop for signal downconversion that is usually integrated in silicon tuner chips, a phase-locked loop that generates a relatively low-frequency clock is also designed for analog-to-digital conversion sampling of received signals. It is reported that the MxL5007T is currently mostly used for cable TV signal reception.

Expert Comments:

ADMTV102 is a product with a relatively high market share and relatively balanced performance. Its disadvantages are slightly higher power consumption and a large number of off-chip components (about 20). The upgraded product ADMTV102, ADMTV803, reduces power consumption to about 90mW. It also integrates many resistors, capacitors and other devices, reducing the number of off-chip components to 6, which is very beneficial to reducing system costs. In addition, its noise coefficient is about 1.5dB lower than that of ADMTV102, and the receiving sensitivity performance is greatly improved.

Since Mxl5007T supports the 44M~1G frequency band and also supports intermediate frequency output, its power consumption is higher than other CMMB tuners; but its power consumption of 300mW is still relatively low among tuners that support the full frequency band.

The area of ​​the Siano 1180 tuner is more than twice that of the ADMTV803, and the cost is higher. The official power consumption of 31mW is the power consumption of time-sharing operation, and the actual power consumption of the tuner should be higher than that of the ADMTV803.

TP3021 integrates Sharp's tuner and many external components, with the highest integration and good sensitivity. However, due to its high price, it is rarely used in practice.

From the actual use and testing of the chip, ADMTV102 is currently the best choice for CMMB applications. In the next 1-2 years, its upgraded product ADMTV803 will have better performance and lower overall cost.

Expert introduction:

Shen Bo received his bachelor's, master's and doctoral degrees in electronic engineering from Fudan University in 1996, 1999 and 2002 respectively. His main research direction is communication integrated circuit design. He has served as a senior manager of Trident Corporation, an associate professor at Fudan University, and the general manager of Shanghai Micro-Tech Integrated Circuit Co., Ltd. He is currently the founder and CTO of Shanghai Shifeng Microelectronics Co., Ltd., mainly engaged in the development of mobile TV demodulators and RF tuners.