A 2.4-GHz 43-dB CMOS Logarithmic Amplifier for RF Signal Level Detection

This paper describes the design and implementation of a 2.4-GHz fully-differential logarithmic amplifier for RF signal power detection. A novel self-bias wideband amplifier without on-chip inductor is employed as a limiting amplifier stage. The proposed logarithmic amplifier is realized and fabricated in a 0.35-mum CMOS technology. Measurement results showed that the circuit achieved 43-dB voltage gain, while drawing 73.5 mA from a single 2.5-V power supply voltage.