A Highly Linear Broadband Variable Gain LNA for TV Applications

A broadband variable-gain low noise amplifier with triple output for TV tuners has been demonstrated in a 0.18 μm SiGe technology. The gain varies continuously from 27 dB to -28 dB and has better than 1 dB precision over a 1GHz bandwidth. At 27 dB gain the amplifier shows 6.5 dB NF, 82 dBmV OIP3 and 121 dBmV OIP2. OIP3 is above 73 dBmV down to -21 dB gain. With all three outputs enabled the circuit draws 170 mA from a 3.3V supply.