The MAX3518 is an integrated CATV upstream amplifier IC designed to meet the DOCSIS 3.0 requirements, while dissipating only 1.25W. The amplifier covers a 5MHz to 85MHz input frequency range (275MHz, 3dB bandwidth), and is capable of transmitting four QPSK modulated carriers, each at +58dBmV, simultaneously within this range. Both input and output ports are differential, requiring that an external balun be used at the output port. The gain is controlled in 1dB steps over a 63dB range using a SPI™ 3-wire interface.
The MAX3518 operates from a single +5V supply. Four power codes are provided to allow maximum supply current to be reduced as determined by distortion requirements. In addition, for each power code, supply current is automatically reduced as gain is reduced while maintaining distortion performance. For DOCSIS 3.0 applications, the MAX3518 draws 300mA at 33dB gain, dropping to 250mA at 31dB gain. The MAX3518 supply current drops to 5mA between bursts to minimize power dissipation in transmit-disable mode. Control logic levels are 3.3V CMOS.
The MAX3518 is available in a 20-pin thin QFN package, and operates over the extended industrial temperature range (-40°C to +85°C).
