Increasing EMI Immunity in novel low-voltage CMOS OpAmps

An easy solution to increase the immunity to Electromagnetic interferences in recent low-voltage CMOS amplifiers is presented. It is based on a simple modification of the input stage, which can be fabricated in standard CMOS technologies and does not require extra mask levels, such as triple well, nor external components. Analysis and results are provide for very large interferences, arising from the input pin.