DOCSIS 3.0 Upstream Amplifier

The MAX3519 is an integrated CATV upstream amplifier IC designed to exceed the DOCSIS 3.0 requirements. 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 MAX3519 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 MAX3519 draws 360mA at 33dB gain, dropping to 300mA at 31dB gain. The MAX3519 supply current drops to 5mA between bursts to minimize power dissipation in transmit-disable mode. Control logic levels are 3.3V CMOS.

The MAX3519 is available in a 20-pin TQFN package, and operates over the extended industrial temperature range (-40°C to +85°C).

Applications

* DOCSIS 3.0 Cable Modems * Set-Top Boxes * VOIP Modems

* Exceeds DOCSIS 3.0 Electrical Requirements

* 63dB Gain Control Range in 1dB Steps

* -63dBc Harmonic Distortion at 64dBmV Output

* Low Burst-On/Off Transient of 25mV at Maximum Gain

* 275MHz, 3dB Bandwidth Supports All Standard Upstream Frequency Plans

* Low-Power Standby Mode Reduces Static Power Consumption

* 25mW Dissipation in Transmit Disable Mode

* Industry-Standard +5V Single-Supply Operation Simplifies Design and Reduces System Cost

* Small, 5mm x 5mm TQFN Package Saves Board Space