Wide-band CMOS loop-through amplifier for Cable TV tuner

A fully integrated loop-through amplifier (LTA) for cable TV tuner is presented in a 0.18 mum CMOS process. It covers the whole frequency band from 48 MHz to 860 MHz and allows a second TV and multiple tuners. This circuit employs a parallel connection of common-gate and common-source (CG-CS) amplifiers for broadband matching. The performances are enhanced by current amplification for high linearity and by noise canceling for low noise figure. There are global and local feedback circuits to achieve wide-band input matching and flat gain. We have achieved a gain of 5 dB, a noise figure (NF) of 8.2 dB, an IIP2 of 78 dBmV, an IIP3 of 59 dBmV and SR₁₁ of -11 dB at 850MHz. The power consumption of the circuit is 92.4mW from a 3.3-V supply and the area of chip is 0.075mm².