An ultra-low-power low-noise analog front end (AFE) is presented in this work, aiming for long-term ECG with clear P-waves for clinical diagnose. The chopper amplifier with passive noise filter and PWM based offset cancellation results in an input-reference noise of 0.39 μVrms, which shows 3.7X noise improvements among the state-of-the-art designs. With the digital offset cancellation by the pulse-width modulation wave, the AFE achieves a low input-referred dc offset of 0.4 μV among 9 tested chips and a low drift under 30 μV. A dynamic scale ADC with low-power comparator strategy prevents the instability and signal-loss, achieving an SFDR of 71.6 dB. The proposed AFE achieves a noise-efficient-factor (NEF) of 2.4 with a power consumption of 4 μW. The fabricated chip is demonstrated in a miniature prototype for long-term ECG monitoring application, presenting a clear ECG waveform with visible P-wave. The simultaneously ECG recording with a medical grade 12-lead ECG Holter shows the effective acquisition of the prototype, proofing the better noise performance.

中文翻译：

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实现 2.4 NEF 的 4μW 模拟前端，用于长期心电图监测


这项工作提出了一种超低功耗低噪声模拟前端（AFE），旨在为临床诊断提供具有清晰 P 波的长期心电图。具有无源噪声滤波器和基于 PWM 的偏移消除的斩波放大器可产生 0.39 μVrms 的输入参考噪声，与最先进的设计相比，噪声改善了 3.7 倍。通过脉宽调制波的数字失调消除，AFE 在 9 个测试芯片中实现了 0.4 μV 的低输入参考直流失调以及 30 μV 以下的低漂移。具有低功耗比较器策略的动态规模 ADC 可防止不稳定和信号丢失，实现 71.6 dB 的 SFDR。所提出的 AFE 的噪声效率因数 (NEF) 为 2.4，功耗为 4 μW。所制造的芯片在长期心电图监测应用的微型原型中进行了演示，呈现出清晰的心电图波形和可见的 P 波。使用医用级 12 导联心电图动态心电图仪进行的同步心电图记录显示了原型的有效采集，证明了更好的噪声性能。