CMOS noise canceling balun LNA with tunable bandpass from 4.6 GHz to 5.8 GHz

Abstract

A compact resistive-feedback low-noise amplifier (LNA) with single-ended input and differential output for multistandard wireless receivers up to 6 GHz is presented. To relax external RF filters and LNA linearity requirements, an on-chip LC bandpass load is included with a continuously tunable center frequency from 4.6 GHz to 5.8 GHz. The LNA is implemented in 65 nm CMOS technology and achieves a measured gain up to 30 dB and an IIP3 linearity between -6.5 dbm and -10.3 dBm. Due to noise cancelation techniques the noise figure (NF) reaches a low value of 1.6 dB in the band of interest. The power consumption is below 16 mW at 1.2 V single supply. The active chip area is 154 µm * 197 µm. Therefore the proposed LNA structure is a costeffective alternative to source-degeneration based narrowband LNA's with comparable performance. Since wide-band input impedance matching is employed, the LNA can be used in reconfigurable multi-standard wireless applications.

Balun LNA Thermal Noise Analysis and Balancing With Common-Source Degeneration Resistor

“…Fig (6) shows the NF comparison between the LNA with and without R SCS . A drop in NF after balancing indicates that R SCS can be used to balance and cancel the transistors thermal noise.…”

“…In [5] Differential Balun LNA was used with BiCMOS, where the CE-stage acts as the error correction stage canceling distortion and noise, although he used degeneration resistors for both CE, there noise contribution was not fully derived nor was the CE noise contribution studied. In [6] four different Balun LNA topologies were explained and studied, deriving a new tunable bandpass topology; again no noise contribution from the CS or the CS degeneration resistor was accounted for. In [7] a Balun LNA was used with a CG stage before the Balun itself for matching purposes, but no CS degeneration resistor was added.…”

A 5.8 GHz RF Receiver Front-End with 77.6 dB Dynamic Range AGC for a DSRC Transceiver

“…To avoid an external passive balun, an active balun must be considered as the solution to provide a differential output for the LNA. The LNA of the receiver is based on a buffered feedback topology [14] which is shown in Fig. 3.…”

“…9 shows the proposed IF-PD. The terms involving 𝑣 𝑖𝑛 2 are responsible for power detection [14]. For the output voltage of PD:…”