EE 214 Lecture 18 (HO#26)B. Murmann2Overview•Reading–8.8.2 (Closed-Loop Impedance Formula using Return Ratio)–6.7 (MOS Active-Cascode Amplifiers)•Reference–K. Bult, G.J.G.M. Geelen, "A fast-settling CMOS op-amp for SC circuits with 90-dB DC gain," IEEE J. Solid-State Circuits, Dec. 1990, pp. 1379 – 1384.•Introduction–In order to complete our framework for feedback circuit analysis, we will study the effect of feedback on port impedances in today's lecture. A useful analytical tool for quick calculations is Blackman's Impedance Formula, which allows us to find port impedances based on a superposition of simple sub-analyses.