GENERAL DESCRIPTION
The AD8325 is a low-cost, digitally controlled, variable gain amplifier optimized for coaxial line driving applications such as cable modems that are designed to the MCNS-DOCSIS upstream standard. An 8-bit serial word determines the desired output gain over a 59.45 dB range resulting in gain changes of 0.7526 dB/LSB.

FEATURES
    Supports DOCSIS Standard for Reverse Path Transmission
    Gain Programmable in 0.75 dB Steps Over a 59.45 dB Range
    Low Distortion at 61 dBmV Output
        –57 dBc SFDR at 21 MHz
        –55 dBc SFDR at 42 MHz
    Output Noise Level
        –48 dBmV in 160 kHz
    Maintains 75 Ω Output Impedance Transmit Enable and Transmit Disable Modes
    Upper Bandwidth: 100 MHz (Full Gain Range)
    5 V Supply Operation
    Supports SPI Interfaces

APPLICATIONS
    Gain-Programmable Line Driver DOCSIS High-Speed Data Modems Interactive Cable Set-Top Boxes PC Plug-in Cable Modems
    General-Purpose Digitally Controlled Variable Gain Block