2022-10-01 10:09 Status: # MOSFET Operating Regions 3 basic operating regions. ## NMOS ## Cutoff VGS < VTH, where VTH > 0V (enhancement mode - almost always the case).  ## Triode VEff = VGS - VTH (overdrive or effective voltage) Vgs > Vth, Vds < Vgs - Vth  ## Saturation Vgs > Vth, Vds > Vgs - Vth  ## Notes Can't actually tell the difference between source and drain in the silicon! Define the source as lowest potential. Vds >= 0 defines the source/drain end. ## Effective Drain Current flow can change direction. ## PMOS ### Cutoff Vgs < Vth where Vth < 0V (enhancement mode) ### Triode Vgs < Vth, Vds > Vgs - Vth Veff = Vgs - Vth (negative) ### Saturation Region Vgs < Vth Vds < Vds - Vth ## Contacts to Substrate Need highly doped contact point because otherwise we form a diode! DRC's won't let you.  ## Diodes  Connect p-substrate to lowest potential. Connect n-well substrate to most positive voltage (Vdd) ## Bulk to Source Voltages  [^1] --- # References [^1]: [vr-4602-wk03-sc01-operratingregions](../../Spaces/University/ELEC4602%20–%20Microelectronics%20Design%20and%20Technology/Lectures/W2/vr-4602-wk03-sc01-operratingregions.mp4)