Topics & Important Concepts
ELEC 312 (W11-12)
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Review of Diode, BJT and MOSFET
(ELEC 311 materials)
1. Semiconductor devices
2. I-V equations
3. DC analysis, DC design
4. AC equivalent circuits
5. AC analysis
6. Voltage gain, Input & Output
resistances
7. Single stage amplifiers
Current Source, Current Mirror &
Active Loads
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Current source using BJT and MOSFET
Design of current source and mirror
Non-idealities
Improved current mirrors
Active loads
Use of active loads in basic amplifiers
Differential Amplifier
• Large signal operation
•AC operation with discrete load
(fully diff.,balanced diff.,single in diff.
Out, Common mode rejection)
•AC operation with active load (diff.
In single out)
Multistage Amplifier
 Operational Amplifier examples
 Diff. Amp, CE, CB, CC (CS,CG,CD for MOS) stages
 Overall gain calculations – take note of the loading at
the inter-stage coupling
 Input, output resistance calculations
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Concepts of 3dB frequencies, dominant poles
Expressing the gain as AM AL AH
Calculations for high-frequency gain (OCTC,
Full Transfer function, use of Miller’s effect
principle)
Frequency response of h fe (~relates to
transition frequency)
Gain- bandwidth calculations
Compound amplifier stages for improved high
frequency (wide-band) response
Frequency Response
of Amplifiers
Negative Feedback Systems
 Basic concept and advantages
 Four types of feedback connection
 Two-port circuit and equation models (only three
parameters are important)
 Calculations with ‘loaded’ amplifier (pay attention to
proper unit of the loaded gain)
 Stability in negative feedback
 Gain margin, phase margin, frequency compensation
Output Stages
• REQUIREMENTS OF AN OUTPUT STAGE
• DIFFERENT DC BIASING
• CLASS A AND B STAGES- EFFICIENCY,
POWER DISSIPATION
• CLASS AB BIASING – CALCULATIONS
•D I F F E R E N T C L A S S A B C O N F I G U R A T I O N S
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HEAT DISSIPATION CONSIDERATIONS
•Transfer function calculations
•Band-edge frequencies and Band-
width calculations
•Barkhausen
condition
• R,C Oscillators (Wein Bridge, Phase shift)
• L,C Oscillators (Colpitts and Crystal)
• Analysis using loop-gain concept
• Analysis using Nodal Admittance Matrix
Equation
Review, Take self test, Practice fast
pace writing
Good luck