Gain Programmable CATV Line Driver

The AD8321 is a low cost digitally controlled variable gain amplifier optimized for coaxial line driving applications such as cable modems that are designed to the DOCSIS* (upstream) standard. An 8-bit serial word determines the desired output gain over a 53.4 dB range, resulting in gain changes of 0.75 dB/LSB.

The AD8321 is packaged in a low cost 20-lead SOIC, operates from a single +9 V supply, and has an operational temperature range of -40°C to +85°C.

An evaluation board is available for this product and may be ordered using the following product number: AD8321-EVAL. Schematic and layout for this evaluation board is contained in the product datasheet.

* Linear in dB Gain Response Over >53 dB Range

* Drives Low Distortion >11 dBm Signal into 75 Ω Load: –53 dBc SFDR at 42 MHz

* Very Low Output Noise Level

* Maintains Constant 75 Ω Output Impedance

Power-Up and Power-Down Condition

No Line Transformer Required