On Schmitt trigger and other inverters

This paper compares classical CMOS versus Schmitt trigger (ST) inverters (INVs), sized both conventionally as well as unconventionally. The reason is that ST INVs are using positive feedback (which leads to hysteresis) and are expected to exhibit much better static noise margins (SNMs) than classical CMOS INVs. That is why ST INVs are more reliable. Lately, quite a few papers have been looking at using ST INVs for implementing SRAMs focusing mainly on the ultra-low voltage/power application range. Here we are going to look at SNM, delay, power and power-delay-product over the whole voltage range for exploring the potential advantages ST could offer in advanced CMOS technology nodes, and better identify their application range.