Electronic Design

Modem Tuner Integrates All Critical RF Elements

Able to dramatically simplify the front-end design of cable tuners, the Hi-IQ tuner chip (DPS7000) from LSI Logic integrates all critical RF elements onto a single chip. By eliminating all the components that require adjustments after shipping, the highly integrated design eliminates factory calibration, improves system reliability, and reduces the bill of materials, thereby lowering overall costs.

Integrated on the DPS7000 are all of the elements of the downconversion receiver: the low-noise amplifiers, the automatic gain controls, the mixers, the phase-locked loops, the IF amplifiers, and the varactors. Only one external SAW filter is required to complete the front end.

This proprietary architecture eliminates the need for tracking filters. The low-noise amplifiers deliver a low noise figure and better than a 6-dB return loss across the entire input frequency range. Also, the chip can re-ceive signals between 48 MHz and 1 GHz, and it delivers an IF output to the baseband PHY demodulators. Supporting both the DOCSIS and DAVIC standards, the DPS7000 provides a selectable 36- or 44-MHz IF output for the selected 6- or 8-MHz channels.

Operating from a 3.3-V supply, the chip consumes just 600 mW—about half the power requirement of solutions that are more discrete-based. The tuner circuit, housed in a 64-lead thin quad-sided flat package, sells for $7.40 each in lots of 10,000 units. Samples are immediately available.

LSI Logic Corp., 1551 McCarthy Blvd., Milpitas, CA 95035; (866) 574-5741; fax (866) 574-5742; www.lsilogic.com.

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