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Analysis and Design of a 260-MHz RF Bandwidth +22-dBm OOB-IIP3 Mixer-First Receiver With Third-Order Current-Mode Filtering TIA Giacomo Pini , Student Member , IEEE
设计适用于5G应用的260MHz带宽、高线性度混频器优先接收器
IIP3 +22dBm, NF 5.5dB, 功耗21.6mW(信号路径)+7.8mW/GHz(LO)
5G接收器混频器优先架构宽带线性化CMOS低功耗设计
▸创新点1：采用改进型调节级联结构增强选择性（方法创新）。该设计摒弃传统并联反馈架构，采用低功耗改进型调节级联结构，显著提升接收机的频率选择性，有效抑制带外干扰，实测IIP3达+22dBm，接近带边缘的线性度大幅改善。
▸创新点2：电流域三阶低通滤波技术（电路创新）。在混频器输出端引入电流域滤波，通过正反馈电容倍增实现三阶低通特性，在260MHz带宽内保持高线性度（IIP2达+70dBm），同时降低功耗至21.6mW。
▸创新点3：正反馈电容倍增技术提升线性度（电路创新）。通过非线性模型验证该技术可优化带边线性度，实测P1dB达+3dBm，在5G应用频段（<6GHz）实现22dBm OOB-IIP3，噪声系数仅5.5dB。
▸创新点4：混合架构系统级优化（系统创新）。结合无源混频器与跨阻放大器，在28nm CMOS工艺下实现7.8mW/GHz的LO功耗效率，整体方案兼顾宽带（260MHz）、高线性与低功耗特性。
Abstract
The design of a mixer-first wideband receiver with RF bandwidth of 260 MHz suitable for 5G applications below 6 GHz is presented. The transimpedance amplifier immediately following the passive mixer is based on a low-power modified regulated cascode with enhanced selectivity, instead of a conven- tional shunt-feedback architecture. At the mixer output, thanks to a positive feedback capacitance multiplication, a third-order low- pass filtering in the current domain is performed. A simplified non-linear model is used to demonstrate that, thanks to the improved selectivity, linearity close to the band edge is highly improved. Wide bandwidth, high linearity, and low power are thus achieved. Measurements on a 28-nm CMOS chip prototype show alternate channel IIP3, IIP2, and P1 dB of +22, +70, and +3 dBm, respectively. Receiver (RX) noise figure (NF) is 5.5 dB, while power consumption is 21.6 mW (in the signal path) and 7.8 mW/GHz (for local oscillator (LO) generation) with 1.8-/1.2-V supply.