A novel capacitively-coupled instrumentation amplifier employing chopping and auto-zeroing

This paper presents a novel low power high precision instrumentation amplifier (IA) for general sensors. By using capacitively-coupled topology, wide input common-mode range, high gain accuracy and low power consumption is achieved. To reduce high output ripples caused by chopping technique and avoid noise aliasing effect due to auto-zeroing technique, these two techniques are employed simultaneously in this novel IA to alleviate their own adverse effects. The designed IA was implemented in SMIC 0.18μm CMOS process, and its core area is 0.28mm². Simulations show that it consumes only 4.5μA current at 1V supply and the equivalent input noise power spectrum density (PSD) is 42.66nV/√Hz around 100Hz.