Miller CE Bedienungsanleitung

Imperial College London – EEE 1L2Autumn 2009 E2.2 Analogue ElectronicsThe Miller Theorem and the Frequency Response of the Common Emitter Amplifier

Imperial College London – EEE 10L2Autumn 2009 E2.2 Analogue Electronics111//1SSSSSinSSSSSSinRVVVRZ ZYRZ ZRRZRZZYπππππ==++===++The Common Emitter amp

Imperial College London – EEE 11L2Autumn 2009 E2.2 Analogue ElectronicsThe Common Emitter amplifier (3)Gain: ()()122111out s m Lvmsss sin LoutvV gZV

Imperial College London – EEE 12L2Autumn 2009 E2.2 Analogue Electronics11BE BinBBECCout CEout CEVIZRIVVIZRIVπ−−⎛⎞∂∂== =⎜⎟∂∂⎝⎠⎛⎞∂∂== =⎜⎟∂∂⎝⎠Input Imp

Imperial College London – EEE 13L2Autumn 2009 E2.2 Analogue ElectronicsFrequency response of the Common Emitter amplifierIf we momentarily neglect C

Imperial College London – EEE 14L2Autumn 2009 E2.2 Analogue ElectronicsDealing with CBCIn the absence of CBCwe know that: ()1out m LBLoutvgZGvZY−==+

Imperial College London – EEE 15L2Autumn 2009 E2.2 Analogue ElectronicsFrequency response of the CE amplifierUse the Miller Theorem to get:12 2The l

Imperial College London – EEE 16L2Autumn 2009 E2.2 Analogue ElectronicsFrequency response of the CE amplifier (2)()()2211223 1223input pole output p

Imperial College London – EEE 17L2Autumn 2009 E2.2 Analogue ElectronicsImportance of the gain-bandwidth product()()2211223 1223input pole output pol

Imperial College London – EEE 2L2Autumn 2009 E2.2 Analogue Electronics• Consider a shunt admittance connected between the input and output of an in

Imperial College London – EEE 3L2Autumn 2009 E2.2 Analogue ElectronicsAn application of the Miller theoremInput impedance of the inverting amplifier

Imperial College London – EEE 4L2Autumn 2009 E2.2 Analogue ElectronicsThe small signal model the of BJT• The model below is useful to frequencies of

Imperial College London – EEE 5L2Autumn 2009 E2.2 Analogue ElectronicsBJT model: impedances and transconductance• The large signal BJT equation give

Imperial College London – EEE 6L2Autumn 2009 E2.2 Analogue ElectronicsBJT model Capacitances• BC junction is reverse biased:– depletion capacitance–

Imperial College London – EEE 7L2Autumn 2009 E2.2 Analogue ElectronicsAn important figure of merit:the BJT Current gain and the transit frequency fT

Imperial College London – EEE 8L2Autumn 2009 E2.2 Analogue ElectronicsAn important figure of merit:the BJT Current gain and the transit frequency fT

Imperial College London – EEE 9L2Autumn 2009 E2.2 Analogue ElectronicsThe Common Emitter amplifier()1111 // 25mV at 290K=17CCCmBE TCCBBEBE BEmCACEC