General Description

The MAX2117 low-cost, direct-conversion tuner is intended for receiving MMDS transmissions in the 470MHz to 1000MHz band. The MAX2117 is designed to be used in consumer set-top boxes and is compatible with most DVB-S demodulators.

The MAX2117 directly converts the QPSK broadcast signals from the antenna to baseband using a broad band I/Q downconverter. The tuner provides differential I and Q outputs to the demodulator IC.

The device includes an LNA and an RF variable-gain amplifier, I and Q downconverting mixers, and baseband lowpass filters with programmable cutoff frequency? control and digitally controlled baseband variable-gain amplifiers. Together, the RF and baseband variable-gain amplifiers provide more than 80dB of gain-control range. The IC is compatible with virtually all QPSK demodulators. The MAX2117 includes fully monolithic VCOs, as well as a complete frequency synthesizer. Additionally, an on chip crystal oscillator is provided along with a buffered output for driving additional tuners and demodulators.

Synthesizer programming and device configuration are accomplished with a 2-wire serial interface. The IC fea tures a VCO autoselect (VAS) function that automatically selects the proper VCO. For multituner applications, the device can be configured to have one of two 2-wire interface addresses. A low-power standby mode is available whereupon the signal path is shut down while leaving the reference oscillator, digital interface, and buffer circuits active, providing a method to reduce power in single and multituner applications.

特性 Features

? 470MHz to 1000MHz Frequency Range

? Monolithic VCO: No Calibration Required

? High Dynamic Range: -75dBm to 0dBm

? 4MHz to 40MHz Integrated Variable BW LP Filters

? Single +3.3V ±5 Supply

? Low-Power Standby Mode

? Address Pin for Multituner Applications

? Differential I/Q Interface

? I2C 2-Wire Serial Interface

? Very Small 28-Pin Thin QFN Package

Applications

?? MMDS