JSSC 2022第1期Digital Circuits0.18μm CMOSNeural Network Accelerator

A 130-dB CMRR Instrumentation Ampliﬁer With Common-Mode Replication

提出一种共模复制技术，实现130dB CMRR和50GΩ输入共模阻抗的仪表放大器。

130dB CMRR, 50GΩ输入共模阻抗, 1.86μA@1.8V, 0.227mm²

仪表放大器共模抑制比共模复制高阻抗低功耗

▸共模复制技术（CM-REP）消除共模电流及其失配效应

▸同时提升CMRR和输入共模阻抗

▸针对输入共模范围和寄生效应的实用技术

Abstract

High common-mode rejection ratio (CMRR) of an analog front end (AFE) requires high intrinsic CMRR of the front-end ampliﬁer with high input common-mode (CM) impedance. This article presents a common-mode replication (CM-REP) technique, which replicates the input CM voltage over the front-end ampliﬁer. By eliminating the CM current ﬂow and its mismatch effect, CM-REP improves CMRR and input CM impedance simultaneously. Implementation considerations regarding the input CM range, on-chip, and off-chip parasitics have been discussed with practical techniques incorporated with the proposed CM-REP. Fabricated in a 0.18- μmC M O S technology, the measured instrumentation ampliﬁer (IA) exhibits >130-dB CMRR and 50-G input CM impedance at 50/60 Hz concurrently. The >110-dB CMRR is achieved with i nput CM up to 900 mV pp and >102-dB total CMRR (TCMRR) is obtained with 1-M || 10-nF mismatch of source impedance. The prototype consumes 1.86 μA from a 1.8-V supply and occupies an active area of 0.227 mm 2.