IEEE Trans Biomed Circuits Syst. 2007 Jun;1(2):136-47. doi: 10.1109/TBCAS.2007.907868.
This paper describes an ultralow-power neural recording amplifier. The amplifier appears to be the lowest power and most energy-efficient neural recording amplifier reported to date. We describe low-noise design techniques that help the neural amplifier achieve input-referred noise that is near the theoretical limit of any amplifier using a differential pair as an input stage. Since neural amplifiers must include differential input pairs in practice to allow robust rejection of common-mode and power supply noise, our design appears to be near the optimum allowed by theory. The bandwidth of the amplifier can be adjusted for recording either neural spikes or local field potentials (LFPs). When configured for recording neural spikes, the amplifier yielded a midband gain of 40.8 dB and a -3-dB bandwidth from 45 Hz to 5.32 kHz; the amplifier's input-referred noise was measured to be 3.06 muVrms while consuming 7.56 muW of power from a 2.8-V supply corresponding to a noise efficiency factor (NEF) of 2.67 with the theoretical limit being 2.02. When configured for recording LFPs, the amplifier achieved a midband gain of 40.9 dB and a -3-dB bandwidth from 392 mHz to 295 Hz; the input-referred noise was 1.66 muVrms while consuming 2.08 muW from a 2.8-V supply corresponding to an NEF of 3.21. The amplifier was fabricated in AMI's 0.5-mum CMOS process and occupies 0.16 mm(2) of chip area. We obtained successful recordings of action potentials from the robust nucleus of the arcopallium (RA) of an anesthesized zebra finch brain with the amplifier. Our experimental measurements of the amplifier's performance including its noise were in good accord with theory and circuit simulations.
本文介绍了一种超低功耗神经记录放大器。该放大器的功率和能效据称是迄今为止报告的最低的神经记录放大器。我们描述了低噪声设计技术，这些技术有助于神经放大器实现接近任何使用差分对作为输入级的放大器的理论极限的输入参考噪声。由于神经放大器在实践中必须包括差分输入对，以允许对共模和电源噪声进行稳健的抑制，因此我们的设计似乎接近理论允许的最佳状态。放大器的带宽可根据记录神经尖峰或局部场电位 (LFP) 进行调整。当配置为记录神经尖峰时，放大器的中频增益为 40.8dB，-3dB 带宽从 45Hz 到 5.32kHz；放大器的输入参考噪声测量为 3.06μVrms，同时从 2.8V 电源消耗 7.56μW 的功率，对应的噪声效率因子 (NEF) 为 2.67，理论极限为 2.02。当配置为记录 LFP 时，放大器的中频增益为 40.9dB，-3dB 带宽从 392mHz 到 295Hz；输入参考噪声为 1.66μVrms，同时从 2.8V 电源消耗 2.08μW 的功率，对应的 NEF 为 3.21。该放大器采用 AMI 的 0.5μm CMOS 工艺制造，占用 0.16mm²的芯片面积。我们使用该放大器成功地从麻醉斑马雀大脑的坚固核记录到了动作电位。我们对放大器性能（包括噪声）的实验测量与理论和电路模拟非常吻合。
