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ECE340 ELECTRONICS I

ECE340 ELECTRONICS I. MOSFET TRANSISTORS AND AMPLIFIERS. MOSFET. METAL-OXIDE-SEMICONDUCTOR FIELD EFFECT TRANSISTOR VOLTAGE - CONTROLLED DEVICE LOW POWER DISSIPATION. MOSFET. METAL. OXIDE. OXIDE. OXIDE. SOURCE. DRAIN. CHANNEL. L. NMOSFET ENHANCEMENT MODE DEVICE. -V S. +V D. +V G.

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ECE340 ELECTRONICS I

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  1. ECE340ELECTRONICS I MOSFET TRANSISTORS AND AMPLIFIERS

  2. MOSFET • METAL-OXIDE-SEMICONDUCTOR FIELD EFFECT TRANSISTOR • VOLTAGE - CONTROLLED DEVICE • LOW POWER DISSIPATION

  3. MOSFET METAL OXIDE OXIDE OXIDE SOURCE DRAIN CHANNEL L

  4. NMOSFET ENHANCEMENT MODE DEVICE -VS +VD +VG METAL OXIDE OXIDE OXIDE N TYPE SOURCE N TYPE DRAIN DEPLETION LAYER DEPLETION LAYER P TYPE SUBSTRATE -VB

  5. MOSFET “ON” CONDITION +VD VG > VTN ID METAL OXIDE OXIDE OXIDE n+ n+ electrons p

  6. MOSFET PARAMETERS • iD – DRAIN CURRENT • VTP,VTN – THRESHOLD VOLTAGE (VTH) • vDS – DRAIN TO SOURCE VOLTAGE • vGS – GATE TO SOURCE VOLTAGE • vB – BULK VOLTAGE

  7. THRESHOLD VOLTAGE • VOLTAGE REQUIRED TO CREATE AN INVERSION LAYER OF CHARGE UNDER THE GATE OXIDE • POSITIVE FOR n-CHANNEL DEVICES • NEGATIVE FOR p-CHANNEL DEVICES

  8. BULK VOLTAGE • LOWEST VOLTAGE AVAILABLE FOR NMOS (N-CHANNEL) DEVICES • HIGHEST VOLTAGE AVAILABLE FOR PMOS (P-CHANNEL) DEVICES • REVERSE-BIASES PN JUNCTIONS

  9. MOSFET CAPACITANCE • POSITIVE OR NEGATIVE VOLTAGE AT GATE TERMINAL INDUCES CHARGE ON GATE METAL • CHARGE OF OPPOSITE TYPE ACCUMULATES IN CHANNEL • FORMS MOSFET CAPACITOR

  10. OXIDE CAPACITANCE

  11. PARAMETER DEFINITIONS • n,p - ELECTRON OR HOLE MOBILITY • ox – PERMITTIVITY OF OXIDE • tox – OXIDE THICKNESS • (W/L) – ASPECT RATIO

  12. MOSFET OPERATION • SOURCE TERMINAL IS GROUNDED • GATE AND DRAIN VOLTAGES REFERENCED TO SOURCE VOLTAGE • VOLTAGE IS APPLIED TO GATE TERMINAL TO INDUCE CHARGE IN THE CHANNEL

  13. CHARGE FLOW • CHARGE IS PULLED INTO CHANNEL FROM DRAIN AND SOURCE REGIONS • CHARGE FLOWS FROM SOURCE TO DRAIN AS DRAIN VOLTAGE IS INCREASED

  14. DEVELOPMENT OF MOSFET EQUATIONS

  15. DEVELOPMENT OF MOSFET EQUATIONS

  16. DEVELOPMENT OF MOSFET EQUATIONS

  17. DEVELOPMENT OF MOSFET EQUATIONS

  18. N-CHANNEL MOSFET EQUATIONS

  19. MOSFET CHARACTERISTICS ID 1.5mA vGS3 1.0mA vGS2 0.5mA vGS1 0mA 0V 2V 4V 6V 8V 10V 12V vDS

  20. TRANSCONDUCTANCE PARAMETER COMPONENTS • MOBILITY • ELECTRIC PERMITTIVITY • OXIDE THICKNESS • ASPECT RATIO

  21. TRANSCONDUCTANCE PARAMETER PHYSICS

  22. n-CHANNEL MOSFET OPERATION IN CUTOFF REGION

  23. n-CHANNEL MOSFET OPERATION IN LINEAR REGION

  24. n-CHANNEL MOSFET OPERATION IN SATURATION REGION

  25. p-CHANNEL MOSFET OPERATION IN CUTOFF REGION

  26. p-CHANNEL MOSFET OPERATION IN LINEAR REGION

  27. p-CHANNEL MOSFET OPERATION IN SATURATION REGION

  28. NMOS INCREMENTAL RESISTANCE IN THE LINEAR REGION

  29. PMOS INCREMENTAL RESISTANCE IN THE LINEAR REGION

  30. MODULATED CHANNEL IN SATURATION REGION VD>>VG +VD VG > VTN ID METAL OXIDE OXIDE OXIDE n+ n+ TAPERED CHANNEL p

  31. NMOS INCREMENTAL RESISTANCE IN SATURATION REGION

  32. PMOS INCREMENTAL RESISTANCE IN SATURATION REGION

  33. DEPENDENCE ON DRAIN VOLTAGE

  34. PSPICE MOSFET SYMBOLS n-channel enhancement p-channel enhancement

  35. NMOS LARGE SIGNAL MODEL G D G + + VDS rO VGS - - S S

  36. DEVELOPMENT OF MOSFET SMALL-SIGNAL MODEL

  37. TOTAL CURRENT AND VOLTAGE

  38. COMPONENTS OF TOTAL CURRENT

  39. MOSFET TRANSCONDUCTANCE

  40. ALTERNATIVE TRANSCONDUCTANCE EQUATION

  41. id d g VCC + + gmvgs vgs vds rO - - s s SMALL-SIGNAL MODEL

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