In a signal-conditioning op-amp application, is there an optimum circuit topology for optimizing SNR and SFDR? Here’s a succinct analysis, part mathematical, part simulation, and part cookbook, from Electronic Design's Don Tuite and Intersil's Michael Steffes that presents the case for transformer-coupling the signal and applying it to the op-amp’s inverting input. Direct coupling and transformer-coupling to the non-inverting input are analyzed and shown to be inferior.
Note, the online version of the article includes new notes and figures not included in this download.