Electronic Design

Complete Tuner For DVB And VSAT Satellite Applications Eliminates LNA

Direct broadcast video (DVB), DirecTV, Dish Network DBS, and very small aperture terminal (VSAT) satellite applications continue to grow, creating a need for a high-performance receiver. Maxim Integrated Products' MAX2112 direct-conversion receiver comes complete with mixers, a synthesized local oscillator, filters, and related support circuits on a single chip.

The chip covers the 925- to 2175-MHz range, which is essentially the IF range where most low-noise block (LNB) converters on the antenna downconvert. The MAX2112 downconverts to baseband and demodulates the signal, making it ready for the TV receiver or video monitor. The outputs are differential I and Q signals.

The receiver is designed for quadrature phase-shift keying (QPSK) and 8PSK modulation and has a low 8.0-dB noise figure. The unusually wide –75- to 0-dBm dynamic range eliminates the need for an external low-noise amplifier (LNA). The fractional-N synthesizer has its own 27-MHz crystal oscillator. The VCO autotuner function simplifies firmware for ease of use. Built-in low-pass filters are variable for 4 to 40 MHz. Programming is by way of an I2C interface.

The MAX2112 comes in a 5- by 5-mm, 28-pin, thin quad-flat no-lead (TQFN) package and draws only 300 mW from its 3.3-V supply. Prices start at $4.50 in quantities of 1000. Evaluation kits and reference designs are available.

Maxim Integrated Products

www.maxim-ic.com

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