说明 The MAX2102/MAX2105* are low-cost direct-conversion tuner ICs designed for use in digital direct-broadcast satellite (DBS) television set-top box units. The direct-conversion architecture reduces system cost compared to devices with IF-based architectures.
The MAX2102/MAX2105 directly tune L-band signals to baseband using a broadband I/Q downconverter. Operating frequency range spans from at least 950MHz to 2150MHz.
The ICs include a low-noise amplifier (LNA) with automatic gain control (AGC), two downconverter mixers, an oscillator buffer with 90° quadrature generator and prescaler, and baseband amplifiers.
The MAX2102 features an AGC range of 50dB, allowing input power levels as low as -69dBm. The MAX2105 has a reduced AGC range of 41dB and accepts input power levels down to -60dBm. The reduced AGC range of the MAX2105 allows the use of a high-gain external LNA to achieve a lower system noise figure (NF).