Smith chart Nonideal effects

Do over exam #1

frequency analysis of a parallel resonant circuit – R = 0; L & C = 1

frequency analysis of a series resonant circuit – R = 0 & 0 frequency analysis of a series resonant circuit – R = 0 & 0.5; L & C = 1

Application of the Smith chart Application of the Smith chart. Transistor circuit – frequency analysis Richard Percifield -- 2007

Model Equation

Transistor Parameters LT = 20nH rbb’ = 50 ohms rb’e = 1000 ohms CT = 100pF Znorm=100 ohms Frequency Range DC to 600MHz

Input Z vs. Frequency Matlab Makes the Plotting Easy! Towbar a

Instability Circles

Important changes in the MOSFET Moore’s Law (Intel Corp. cofounder) The number of active elements on a chip doubles every 18 months.

Important changes in the MOSFET Assume constant electric field scaling!

Important changes in the MOSFET

Important changes in the MOSFET

Important changes in the MOSFET Material determination weak dependence on k

Problem in changing the MOSFET We will not change our old power supplies. Do not, I repeat, do not change the voltage supplies so often. Consequences electric fields increase in value. 2) reduced reliability. 3) heating

Nonideal defects in the MOSFET Laboratory experiment

Modulate the channel length of the MOSFET

Modulate the channel length of the MOSFET

Modulate the channel length of the MOSFET Electron mobility is a function of the electric field and the temperature.

Ideal MOSFET Long channel G V Space charge regions Flatband

Ideal MOSFET Short channel G V Space charge regions Flatband

Ideal MOSFET G V

Ideal MOSFET V As L decreases, inversion channel becomes a depletion layer G V

Important changes in the MOSFET Material determination weak dependence on the change of the dimension k

Important changes in the MOSFET

Important changes in the MOSFET

Summary of changes in a MOSFET

Asymmetric MOSFET Short channel G V G V Space charge regions Flatband

Picture from Saturn

Simple three-dimensional unit cell