Introduction to circuit design and SPICE simulations
  • Why do we need circuit design and SPICE simulations?
  • Introduction to basic element in circuit design - NMOS
  • Strong inversion and threshold voltage
  • Threshold voltage with positive substrate potential
NMOS Resistive region and saturation region of operation
  • Resistive region of operation with small drain-source voltage
  • Drift current theory
  • Drain current model for linear region of operation
  • SPICE conclusion to resistive operation
  • Pinch-off region condition
  • Drain current model for saturation region of operation
Introduction to SPICE
  • Basic SPICE setup
  • Circuit description in SPICE syntax
  • Define technology parameters
  • Standard technology file
  • First SPICE Simulation
  • SPICE deck for 1.2u Technology node
SPICE simulation for lower nodes and velocity saturation effect
  • SPICE simulation for lower nodes (250nm)
  • SPICE deck for 250nm Technology node
  • Drain current vs gate voltage for long and short channel device
  • Id-Vgs SPICE deck for 1.2u technology node
  • Id-Vgs SPICE deck for 250nm technology node
  • Velocity variation at lower and higher electric fields
  • Velocity saturation drain current model
CMOS voltage transfer characteristics
  • MOSFET as a switch
  • Introduction to standard MOS voltage current parameters
  • PMOS NMOS drain current v/s drain voltage
  • Step1 - Convert PMOS gate-source-voltage to Vin
  • Step2 & Step3 - Convert PMOS and NMOS drain-source-voltage to vout
  • Step4 - Merge PMOS - NMOS load curves and plot VTC
Conclusion and next steps
  • Conclusion and next steps
Quiz
  • Threshold voltage