A CMOS source-buffered differential input stage with high EMI suppression

This paper introduces a CMOS source-buffered differential input stage exhibiting a high degree of immunity against electromagnetic interferences (EMI) which are applied on its input pins. The measurements of a test-IC illustrate that the source-buffered differential pair generates a maximal EMI induced input offset voltage of 116 mV when a 750 mV RMS EMI signal is injected in its inputs, while a classic differential pair output is saturated with a maximal offset of 610 mV under the same circumstances.