Broadband Balun-LNA Employing Local Feedback g m -Boosting Technique and Balanced Loads for Low-Power Low-Voltage Applications

Abstract

A new low-voltage and low-power noise-cancelling method that employs the local feedback $g_{m}$ -boosting and balanced loads is proposed by developing a design for a low-noise and low-power balun-low-noise amplifier (LNA) for low-power broadband applications. A common-gate (CG) – common-source (CS) balun-LNA with a modified current-bleeding (CBLD) technique has low noise performance and differential balanced output but consumes more power. Because local feedback boosts the overall $g_{m}$ of the CG stage using the amount of loop gain, the current consumption and supply voltage requirements can be mitigated. In addition, the cross-coupled cascode stage acts as a differential current balancer to improve the gain and phase mismatches at the differential output. Implemented in a 65-nm CMOS technology, the balun-LNA achieves a noise figure of 2.3 - 3 dB, a maximum voltage gain of 27.5 dB and a $S_{11}$ of less −10 dB over the frequency range of 50 MHz to 1.3 GHz. The measured OIP3 and OIP2 are 25.3 dBm and 45.3 dBm, respectively. It consumes 5.7 mA from a nominal supply voltage of 1 V while the active die area is 0.046 mm2.