Electronic Design

Poly-Band Mobile Broadcast Tuner Makes Adding Radio/TV A Snap

The mobile nature of broadcast radios and TVs becomes more evident all the time, appearing in myriad devices like cell phones and MP3 players.

For example, take analog radio. There's AM and FM. Or, try a National Oceanic and Atmospheric Agency FM weather radio or an AM shortwave radio for the 3- to 30-MHz band. Neither is easy. Then there's digital radio. The more common digital formats are Digital Audio Broadcast (DAB) and Digital Radio Mondiale (DRM), each with its own unique requirements.

TV is also finding its way into cell phones. If making a suitable front end weren't such a devil of a job, we might see it in more portable devices as well. DVB-H and MediaFLO are well on their way, and other systems are being developed worldwide. With the baseband functions assigned to one or more processors, all one needs is an RF front-end.

With Mirics Semiconductor's breakthrough MS1001 polyband tuner, adding broadcast reception capabilities to new products can be a relatively simple task. Designers of mobile phones, portable media players, PDAs, and even laptops and auto radios will be able to easily add mobile broadcast reception to fit any global standard. The good news is that you can use this single chip for virtually any radio or TV feature in another product. One size does fit all.

The MS1001 provides universal digital broadcast reception capabilities, making it truly independent of international standards or regional differences. It can receive all of the broadcast standards that have been announced to date. Therefore, it can handle any analog radio format across all terrestrial broadcast bands, as well as standard AM and FM bands. It also can deal with all current digital terrestrial broadcast standards.

Some of the most common digital standards include Digital Video Broadcast-Handset (DVB-H), Terresterial-Digital Media Broadcast (T-DMB), Integrated Services Digital Broadcast-Terrestrial (ISDB-T), Digital Audio Broadcast-Internet Protocol (DAB-IP), MediaFLO, Digital Audio Broadcast (DAB), and Digital Radio Mondiale (DRM). The MS1001's frequency range is 100 kHz to 1.9 GHz.

The best thing about the MS1001 is that it can be configured for almost any other standard—even the unknown standards of the future—without any cost or performance penalty. How can you be sure your design will be compatible with the impending Chinese mobile digital TV standard? Just use the MS1001.

Mirics has yet to explore the use of the MS1001 in U.S. ATSC high-definition TV or HD Radio products. But it isn't very likely that ATSC HDTV is ever going to be a portable or mobile standard. HD Radio already has reached that stage.

"The mobile broadcast market is extremely fragmented by multiple standards and band allocations. To date, companies have typically focused on supporting one or two of the multitude of standards," says Simon Atkinson, Mirics' CEO.

"This fragmentation has been identified as the principal bottleneck to the wider adoption of mobile broadcast technologies," he adds. The small volumes that are available for any handset supporting a single standard do not justify its development.

"The multistandard TV tuner has been heralded as the 'holy grail ambition' for mobile handset design, and it's a key development target of our competitors for the next 12 months," Atkinson explains. Mirics, though, is delivering this technology today.

The MS1001 offers multiple front-end inputs for LW/MW/SW (150 kHz to 30 MHz), VHF Band II (76 to 108 MHz), Band III (174 to 240 MHz), Band IV/V (470 to 960 MHz), and L-band (1450 to 1675 MHz) (Fig. 1). Separate low-noise amplifiers (LNAs) are provided, in addition to all input switching. A few capacitors are needed on the front end for impedance matching.

The LW/MW input is designed to take an external ferrite antenna. Most of these inputs may be connected in a balanced or unbalanced configuration. The typical input impedance is 75 or 100 Ω. An external balun is needed on the L-band input.

A fast-settling fully integrated synthesizer drives the I/Q mixers. An external crystal reference is required, but the master oscillator in a cell phone or other host device usually will supply it. The IF may be set to a low IF value (typically 450 kHz or less) or zero for direct conversion. The IF/baseband does the filtering once the mixers are fully programmable from 300 kHz to 4 MHz.

The automatic-gain-control (AGC) amps are available at the outputs to be sent to the analog-to-digital converters (ADCs) and baseband processor for signal recovery. The output voltage ranges up to a 4-V p-p differential. A three-wire serial port is used for all programming and control. The external parts count is very low, but it depends significantly on the bands and modes being used.

Power consumption is another crucial specification when making a chip for battery-powered devices. The MS1001 was designed with low-power operation in mind. In fact, the company claims that the chip has the lowest power consumption of any tuner announced to date.

As an example, it draws only 46 mA when operating in the L-band with DVB-H mobile TV. Power consumption drops to 13 mW with the 10% time-slicing that's a part of the DVB-H standard. In powered-down mode, the chip draws less than 10 A.

The MS1001, which comes in a 6- by 6-mm, 40-pin quad flat no-lead package, costs $3.50 in 10,000-unit quantities. Samples are available now. A customer sample board goes for $1000 (Fig. 2).

Mirics Semiconductor Inc.

TAGS: Mobile
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