AD8325ARU-REEL

The AD8325 is a low-cost, digitally controlled, variable gain ampli-fier 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.

The AD8325 comprises a digitally controlled variable attenuator of 0 dB to 59.45 dB, which is preceded by a low noise, fixed gain buffer and is followed by a low distortion high power ampli-fier. The AD8325 accepts a differential or single-ended input signal. The output is specified for driving a 75 load, such as coaxial cable.

Distortion performance of57 dBc is achieved with an output level up to 61 dBmV at 21MHz bandwidth. A key performance and cost advantage of the AD8325 results from the ability to maintain a constant 75 output impedance during Transmit Enable and Transmit Disable conditions. In addition, this device has a sleep mode function that reduces the quiescent current to 4mA.

The AD8325 is packaged in a low-cost 28-lead TSSOP, operates from a single 5 V supply, and has an operational temperature range of 40°C to +85°C.