A 2.2 NEF Neural-Recording Amplifier Using Discrete-Time Parametric Amplification

This paper proposes a 2.2 noise efficiency factor (NEF) instrumentation amplifier for neural recording applications. A parametric amplifier based on the MOS C-V characteristic is designed as a pre-amplifier stage, lowering the input referred noise of the following stages by 3.4×. Sampling noise is minimized by oversampling the input signal and switching power is reduced by adopting an 8-phase soft-charging technique.