Local field potential measurement with low-power area-efficient neural recording amplifier

Local field potential (LFP) has been of growing interest in interpreting specific motor activities and higherlevel cognitive functions for neurophysiological investigation. LFP denote the neural activity recorded from the ensemble of neurons which carry information in the frequency range of 1-200 Hz. The requirements on the electronics of an amplifier sensor used to measure LFP signals is very stringent, especially with respect to size and power consumption. This work presents an ultra-low power, low noise, area-efficient CMOS neural recording amplifier for LFP recording application. A neural preamplifier implemented with an all weak inversion region OTA achieves 31.7 dB of gain consuming 68.35 nW of power and has an input referred noise of 5.62 μV_rms over 100 Hz of bandwidth. With the large input capacitor integrated on-chip the single channel neural amplifier occupies 0.098 mm² of chip area.