GENERAL DESCRIPTION

The AD8326 is a high-output power, digitally controlled, variable gain amplifier optimized for coaxial line driving applications such as data and telephony cable modems that are designed to the MCNS-DOCSIS upstream standard. An 8-bit serial word determines the desired output gain over a 53.5 dB range resulting in gain changes of 0.75 dB/LSB. The AD8326 is offered in two models, each optimized to support the desired output power and resulting performance.

FEATURES

Supports DOCSIS Standard for Reverse Path

Transmission

Gain Programmable in 0.75 dB Steps over a 53.5 dB Range

Low Distortion at 65 dBmV Output

–62 dBc SFDR at 21 MHz

–58 dBc SFDR at 65 MHz

1 dB Compression of 25 dBm at 10 MHz

Output Noise Level

–45 dBmV in 160 kHz

Maintains 75 Ω Output Impedance

Power-Up and Power-Down Condition

Upper Bandwidth: 100 MHz (Full Gain Range)

Single or Dual Supply Operation

APPLICATIONS

Gain-Programmable Line Driver

CATV Telephony Modems

CATV Terminal Devices

General-Purpose Digitally Controlled Variable Gain Block