Electronic Design

Single-Chip RF Tuners Kick The Can And Make Portable TV Practical

In most TV sets, the front-end RF tuners come in a metal shield can. But they’re slowly disappearing as single-chip tuners have become available. While these devices work nicely in newer TV sets, they also make it possible to package TV reception in cell phones, laptops, and other portable devices.

The MAX3540 single-conversion tuner from Maxim Integrated Devices targets legacy NTSC analog TV as well as the newer U.S. digital TV standard from ATSC (see the figure). It integrates a tracking filter and high-linearity front end, consuming just 760 mW and meeting the sensitivity and adjacent channel guidelines specified by ATSC Recommended Practice A/74.

The device incorporates both RF and IF automatic gain control (AGC) amplifiers and requires only a single external surface acoustic wave (SAW) filter. The input frequency is the standard 54- to 860-MHz range, and the IF output is 44 MHz. The device is compatible with most existing ATSC and NTSC demodulators. The package is a 7- by 7-mm, 48-pin flip chip that operates from a 3.3-V supply. Prices start at $5.90 in 1000-unit quantities. An evaluation kit is available.

Also, the Mirics MSi002 silicon-germanium tuner covers the entire terrestrial broadcast spectrum from 150 kHz to 1.9 GHz. It can be used in any analog or digital radio or TV product with common standards like DVB-H, ISDB-T, T-DMB, and MediaFLO, as well as with the DAB, DRM, AM, and FM radio standards. This chip makes it easy to design portable TV products as well as add radio to cell phones, laptops, or other products.

The tuner’s IF is programmable from 0 to 2 MHz. Zero IF (direct conversion) is a prerequisite for operating in DVB-H or MediaFLO. A low IF usually is selected for ISDB-T, T-DMB, or DAB. In any case, the programmability makes it possible to optimize the design for minimum power consumption. The device is available now. Check with the manufacturer for pricing.

Maxim Integrated Products

www.maxim-ic.com

Mirics Semiconductor

www.mirics.com

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