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Analog Angle Article

TV tuner IC captures analog, digital standards, features LNA and tracking filters for superior performance

Austin, Texas—The CMOS Si2170 IC from Silicon Laboratories, Inc. provides a complete TV tuner for analog and digital signals in a single monolithic device, greatly reducing the number of external support components commonly needed by existing solutions (typically about 100 such components, SiLabs maintains) while increasing RF performance. The silicon tuner includes a highly linear front end with what SiLabs calls a unique, merged low-noise amplifier (LNA) and high-Q tracking filter, which combine to provide gain only around the channel of interest. As a result, the tuner provides excellent sensitivity for that channel, while rejecting strong, adjacent but undesired channels and noise or other interference.

The design supports analog and digital TV standards, including ATSC/QAM, DVB-TC, ISDB-T/C, NTSC, PAL, and SECAM. The Si2170 does not need external LNAs, SAW filters, or tracking filters, while the internal tracking filter eliminates the need for manual tuner adjustment of discrete inductors in the factory as well as drift of units once in the field, neither of which is a good situation. Outputs of the device include CVBS+ SIF/AF to an AV processor, and LIF or ZIF I/Q to a digital TV demodulator, and the IC interfaces with their Si2165 DVB-T/C demodulator for a complete terrestrial and cable hybrid PAL/SECAM and DVB-T/C receiver, as well.



Block diagram of Silicon Laboratories Si2170 TV tuner

(Click on image to enlarge)

Input frequency range is 43 to 1002 MHz, with a noise figure at maximum gain of 4 dB (typical). Other typical specifications include wideband IIP3 is +23 dBm, and inband IIP3 is -2 dBm, both at maximum gain, receiver sensitivity ofis -68 dBm (NTSC) and -67.5 dBm (PAL/SECAM); unweighted video SNR of 54 dB across all signal formats, and adjacent-channel attenuation of 80 dB. —Bill Schweber

Packaging, price, and availability : The 7×7 mm, 48-lead QFN device operates from 1.8 and 3.3 V supplies, with typical dissipation of 1 W. It is available now, priced at $3.95 (10k orders).

For more information : contact Silicon Laboratories, Inc., http://www.silabs.com.

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