A WIDEBAND CMOS CASCADED VARIABLE GAIN AMPLIFIER USING UNEQUALLY DISTRIBUTED GAIN CONTROL FOR DVB-S.2 RECEIVER
2013 ◽
Vol 22
(09)
◽
pp. 1340008
◽
Keyword(s):
A fully integrated three stage cascaded radio frequency variable gain amplifier (RFVGA) linearly controlled by exponential current generation circuit is presented. The gain control is unequally distributed in each stage for noise figure (NF) and linearity performance. The dB-linear gain control is realized using pseudo exponential current generated by CMOS current summing circuit with a voltage to current converter. The RFVGA has over 50 dB dynamic range. Gain changes from -38.5 to 16.8 dB according to control voltage that varies from 0.5 to 1.8 V. It operates at 0.95–2.15 GHz. This design is implemented in 0.18 μm CMOS technology.