1 / 28

Two Stage Amplifier Design

Two Stage Amplifier Design. ENGI 242 ELEC 222. HYBRID MODEL PI. HYBRID MODEL PI PARAMETERS. Parasitic Resistances r b = r b’b = ohmic resistance – voltage drop in base region caused by transverse flow of majority carriers, 50 ≤ r b ≤ 500

micah
Télécharger la présentation

Two Stage Amplifier Design

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Two Stage Amplifier Design ENGI 242 ELEC 222

  2. HYBRID MODEL PI ENGI 242/ELEC 222

  3. HYBRID MODEL PI PARAMETERS • Parasitic Resistances • rb = rb’b = ohmic resistance – voltage drop in base region caused by transverse flow of majority carriers, 50 ≤ rb ≤ 500 • rc = rce = collector emitter resistance – change in Ic due to change in Vc, 20 ≤ rc ≤ 500 • rex = emitter lead resistance – important if IC very large, 1 ≤ rex ≤ 3 ENGI 242/ELEC 222

  4. HYBRID MODEL PI PARAMETERS • Parasitic Capacitances • Cje0 = Base-emitter junction (depletion layer) capacitance, 0.1pF ≤ Cje0 ≤ 1pF • C0 = Base-collector junction capacitance, 0.2pF ≤ C0 ≤ 1pF • Ccs0 = Collector-substrate capacitance, 1pF ≤ Ccs0 ≤ 3pF • Cje = 2Cje0 (typical) • 0 =.55V (typical) • F = Forward transit time of minority carriers, average of lifetime of holes and electrons, 0ps ≤ F ≤ 530ps ENGI 242/ELEC 222

  5. HYBRID MODEL PI PARAMETERS • r = rb’e = dynamic emitter resistance – magnitude varies to give correct low frequency value of Vb’e for Ib • r = rb’c = collector base resistance – accounts for change in recombination component of Ib due to change in Vc which causes a change in base storage • c = Cb’e = dynamic emitter capacitance – due to Vb’e stored charge • c = Cb’c = collector base transistion capacitance (CTC) plus Diffusion capacitance (Cd) due to base width modulation • gmV = gmVb’e = Ic – equivalent current generator ENGI 242/ELEC 222

  6. Hybrid Pi Relationships  = gm r ENGI 242/ELEC 222

  7. Hybrid Pi Relationships ENGI 242/ELEC 222

  8. Design of a Two Stage Amplifier ENGI 242/ELEC 222

  9. Two Stage Amplifier Design Specifications Design a two stage common emitter amplifier with partial emitter bypass for the following specifications: VCC = 20V VE = .1VCC RE1A = .25RE1 VC1 = .6VCC IC1 = 2mA RE2A = .4RE2 VC2 = .55VCC IC2 = 2.5mA R2 = .1RE1 R4 = .1RE2 RL = 10k fCL1 = 16Hz fCL2 = 13Hz fCL3 = 12Hz fCL4 = 67Hz fCL5 = 8Hz For both stages:  = 140 CB = 150ps VA = 100V C 8pF fT = 150MHz rb = 19 ENGI 242/ELEC 222

  10. Hybrid Pi Model ENGI 242/ELEC 222

  11. Low Critical Frequencies • There is one low critical frequency for each coupling and bypass capacitor • We start by determining the (Thevenin) impedance seen by each capacitor • Then we construct a RC high pass filter (output across Z) • We may then calculate the critical frequency by letting |XC| = Z and solving for either fCL or C and fCL = fCL1 + fCL2 + fCL3 + fCL4 + fCL5 ENGI 242/ELEC 222

  12. Hybrid Pi Model Input First Stage ENGI 242/ELEC 222

  13. Hybrid Pi Model Output First Stage ENGI 242/ELEC 222

  14. Hybrid Pi Model Input Second Stage ENGI 242/ELEC 222

  15. Hybrid Pi Model Output Second Stage ENGI 242/ELEC 222

  16. Hybrid Pi Model Emitter Bypass First Stage ENGI 242/ELEC 222

  17. Hybrid Pi Model Emitter Bypass Second Stage ENGI 242/ELEC 222

  18. fCL1 ENGI 242/ELEC 222

  19. fCL2 Determine the Thevenin Impedance seen by C2 ENGI 242/ELEC 222

  20. fCL3 Determine the Thevenin Impedance seen by C3 ENGI 242/ELEC 222

  21. fCL4 Determine the Thevenin Impedance seen by CE1 ENGI 242/ELEC 222

  22. fCL5 Determine the Thevenin Impedance seen by CE2 ENGI 242/ELEC 222

  23. Schematic of Design ENGI 242/ELEC 222

  24. Simulation Profile ENGI 242/ELEC 222

  25. Probe Plot – Y Axis Settings ENGI 242/ELEC 222

  26. Probe Plot – X Axis X Grid Settings ENGI 242/ELEC 222

  27. Frequency Response ENGI 242/ELEC 222

  28. Frequency Response ENGI 242/ELEC 222

More Related