Variable gain DOCSIS 3.0 amplifier

May 30, 2012 // By Jean-Pierre Joosting
The TAT2814A from TriQuint Semiconductor is an RFIC for DOCSIS 3.0 Output Sections, such as CMTS and Edge QAM. It combines a low-reflection differential input stage, a variable gain step attenuator with 18 dB typical range and an efficient output amplifier to provide significant reduction in power consumption and PC board space. It replaces circuitry requiring up to 10x the board space and 2x the power.

The RFIC meets the stringent DOCSIS 3.0 output linearity specifications with extra margin to overcome additional losses before the output connector.

Key specifications include meeting DOCSIS 3.0 requirements with +4 dB typical performance margin, 18 dB typical return loss across entire gain range, 30 dB typical maximum gain, +49 dBm typical OIP3, and 2.7 dB typical noise figure. Typical input stage bias is 5 V, 290 mA, while typical output stage bias is 8 V, 415 mA.

The TAT2814A comes in an industry standard 7- x 7-mm 48-pin QFN and consumes less than 5 W between a 5 V input amplifier supply and an 8 V output amplifier supply. The device utilizes proven GaAs pHEMT at Edge QAM optimized voltage to significantly reduce power consumption of the output stage.