GENERAL DESCRIPTION

The AD8327 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 48.16 dB range resulting in gain changes of 6.02 dB/major carry.

FEATURES

Supports DOCSIS Standard for Reverse Path

Transmission

Gain Programmable in 6.02 dB Steps over a 48.16 dB

Range

Low Distortion at 60 dBmV Output

–63 dBc SFDR at 21 MHz

–57 dBc SFDR at 42 MHz

Output Noise Level

–47 dBmV in 160 kHz

Maintains 75 Ω Output Impedance

Transmit Enable and Transmit Disable Modes

Upper Bandwidth: 160 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