基于变压器反馈的平坦噪声系数超宽带CMOS低噪声放大器

在系统中集成超宽带(UWB)收发机芯片用于支持室内定位正成为移动通信终端技术发展的一个重要趋势.在超宽带收发机中,低噪声放大器(LNA)是一个核心功能模块.超宽带的全频段(3.1～10.6 GHz)覆盖要求给低噪声放大器的设计带来了巨大挑战,尤其是需要在宽带匹配及在带内维持平坦的噪声系数的情况下.传统的低噪声放大器架构应用在超宽带设计时,噪声、增益和输入匹配之间存在较明显的性能折中关系,因此无法达到良好的综合性能指标要求.本文采用基于变压器反馈的输入匹配的第一级架构和多功能第二级输出驱动结构,实现了平坦的噪声系数和高增益等性能.基于TSMC 65 nm工艺设计的电路仿真结果表明,该低噪声放大器在3.1～10.6 GHz全频段内,可实现输入匹配S_(11)-10 dB,增益17 dB,噪声系数2.71±0.28 dB,1-dB压缩点-17.5 dBm等指标,电路整体功耗为32.8 mW.因此,综合性能Ⅰ(FoM-Ⅰ)和综合性能Ⅱ(FoM-Ⅱ)分别可达2.32和0.41.

An ultra-wideband CMOS LNA featuring flat noise figure based on transformer feedback

Indoor positioning technology is becoming more and more widely deployed in recent years.An important technology trend for mobile communication terminals is that Ultra-WideBand (UWB) transceiver SoCs (System-on Chips) being integrated into the system to support indoor positioning.As a key building block in UWB transceivers, the Low Noise Amplifier (LNA) is of full challenges to design mainly due to the full-band (3.1-10.6 GHz) coverage, wide-band input matching and flat Noise Figure (NF) requirements.Conventional LNA topologies typically suffer from severe compromise among noise figure, gain and input matching, resulting in very limited Figure of Merit (FoM).This paper presents a two-stage LNA for UWB application.The first stage is based on transformer-feedback input matching while the second stage employs multi-functional output driver, achieving flat NF and high gain.Designed in TSMC 65 nm CMOS, simulation results show that the LNA achieves S₁₁<-10 dB, gain >17 dB, NF of 2.71±0.28 dB, and 1 dB compression point of -17.5 dBm while consuming 32.8 mW from a 1.2 V supply, corresponding to FoM-I of 2.32 and FoM-II of 0.41, respectively.