A Fully Integrated Inductorless Low Noise Amplifier with 1dB-Step Programmable Gain for FM Radio Receiver Front-End

Abstract

This paper presents a low-voltage low-power programmable gain low noise amplifier (PGLNA) for a frequency modulation (FM) radio receiver front-end. The proposed PGLNA employs two variablegain stages with resistor network feedback loop for DC-offset cancellation and a gain control block. The two-stage LNA achieves a programmable small signal voltage gain from +2.5 dB to +34.5 dB in around 1 dB steps across the FM band from 76 MHz to 108 MHz. In the high and low gain modes, the measured input-referred noise over 150 kHz FM channel bandwidth is 0.36 µV and 2.4 µV, respectively. The PGLNA's IIP3 in the low gain mode is -5.2 dBm. It draws only 4.5 mA current from a 1.35-V supply in the high gain mode and occupies 0.15 mm 2 of chip area excluding bondpads. Experimental results are included to demonstrate and verify the performance of the PGLNA.