HKN ECE 342 Review Session 2 Anthony Li

HKN ECE 342 Review Session 2 Anthony Li Milan Shah

MOSFET’s • NMOS • PMOS

MOSFET Operating Point ●

MOSFET Incremental Model ●

Gain Calculation Av = -GMRout GM = Small signal transconductance, ratio of iout to vin ROUT = Equivalent incremental output resistance

Common Amplifier Topologies 1. 2. 3. 4. 5. Diode-tied Transistor Common Source/Drain/Gate Common Source with Degeneration Common Drain with Modulation Cascode 1. Diode Tied Transistor

Diode-Tied Transistor ● 1. Diode Tied Transistor

Common Source/Drain/Gate ● ● ●

Degeneration When a resistance is “viewed” through the drain, it appears bigger by a factor related to the transconductance. ●

Modulation Resistances seen through the source seem smaller: ●

Cascode

BJT

Regions of Operation ● ● Three regions of operation: Cutoff: VE > VB < VC Saturation: VE < VB > VC Forward Active: VE > VB > VC ○ ○ VT = kt/q IC = �IB IE = IC + IB �= gm. R��

BJT Small Signal Model

Terminal Impedance ● 1. Diode Tied Transistor

Common Emitter/Collector/Base

Degeneration When a resistance is “viewed” through the collector, it appears bigger by a factor related to the transconductance.

Modulation Resistances seen through the Emitter seem smaller.

Bode Plots Magnitude Pole: Roll down by 20 db/dec, 6 db/oct Zero: Roll up by 20 db/dec, 6 db/oct Phase: arctan(ω/ωp) Usually -90° for poles, +90° for zeros ωugf = 20 log|An| * ωpn where n is the pole located before unity gain frequency

Miller Effect ●

Problem 1: Midterm 3 Fa 17

Problem 2: Midterm 2 Fa 16

Problem 3: Midterm 2 Fa 16 ●