PJ
Uploaded byPatel Jay
PPT, PDF5,959 views

Frequency response

This chapter discusses the frequency response of amplifiers. It begins with fundamental concepts and high-frequency models of transistors. It then analyzes the frequency response of common emitter, common source, common base, and common gate stages. Additional topics covered include frequency response of followers, cascode stages, differential pairs, and more examples. Analysis methods like Bode plots, pole identification, and Miller's theorem are explained. Key factors that influence frequency response like bandwidth, gain rolloff, and various transistor capacitances are also analyzed.

Embed presentation

Downloaded 136 times
Chapter 11 Frequency Response  11.1 Fundamental Concepts  11.2 High-Frequency Models of Transistors  11.3 Analysis Procedure  11.4 Frequency Response of CE and CS Stages  11.5 Frequency Response of CB and CG Stages  11.6 Frequency Response of Followers  11.7 Frequency Response of Cascode Stage  11.8 Frequency Response of Differential Pairs  11.9 Additional Examples 1
Chapter Outline CH 11 Frequency Response 2
CH 11 Frequency Response 3 High Frequency Roll-off of Amplifier  As frequency of operation increases, the gain of amplifier decreases. This chapter analyzes this problem.
Example: Human Voice I  Natural human voice spans a frequency range from 20Hz to 20KHz, however conventional telephone system passes frequencies from 400Hz to 3.5KHz. Therefore phone conversation differs from face-to-face conversation. CH 11 Frequency Response 4 Natural Voice Telephone System
Example: Human Voice II CH 11 Frequency Response 5 Mouth RecorderAir Mouth EarAir Skull Path traveled by the human voice to the voice recorder Path traveled by the human voice to the human ear  Since the paths are different, the results will also be different.
Example: Video Signal  Video signals without sufficient bandwidth become fuzzy as they fail to abruptly change the contrast of pictures from complete white into complete black. CH 11 Frequency Response 6 High Bandwidth Low Bandwidth
Gain Roll-off: Simple Low-pass Filter  In this simple example, as frequency increases the impedance of C1 decreases and the voltage divider consists of C1 and R1 attenuates Vin to a greater extent at the output. CH 11 Frequency Response 7
CH 11 Frequency Response 8 Gain Roll-off: Common Source  The capacitive load, CL, is the culprit for gain roll-off since at high frequency, it will “steal” away some signal current and shunt it to ground. 1 ||out m in D L V g V R C s   = −  ÷  
CH 11 Frequency Response 9 Frequency Response of the CS Stage  At low frequency, the capacitor is effectively open and the gain is flat. As frequency increases, the capacitor tends to a short and the gain starts to decrease. A special frequency is ω=1/(RDCL), where the gain drops by 3dB. 1222 + = ωLD Dm in out CR Rg V V
CH 11 Frequency Response 10 Example: Figure of Merit  This metric quantifies a circuit’s gain, bandwidth, and power dissipation. In the bipolar case, low temperature, supply, and load capacitance mark a superior figure of merit. LCCT CVV MOF 1 ... =
Example: Relationship between Frequency Response and Step Response CH 11 Frequency Response 11 ( ) 2 2 2 1 1 1 1 H s j R C ω ω = = + ( ) ( )0 1 1 1 expout t V t V u t R C  − = − ÷    The relationship is such that as R1C1 increases, the bandwidth drops and the step response becomes slower.
CH 11 Frequency Response 12 Bode Plot  When we hit a zero, ωzj, the Bode magnitude rises with a slope of +20dB/dec.  When we hit a pole, ωpj, the Bode magnitude falls with a slope of -20dB/dec           +        +       +      + = 21 21 0 11 11 )( pp zz ss ss AsH ωω ωω
CH 11 Frequency Response 13 Example: Bode Plot  The circuit only has one pole (no zero) at 1/(RDCL), so the slope drops from 0 to -20dB/dec as we pass ωp1. LD p CR 1 1 =ω
CH 11 Frequency Response 14 Pole Identification Example I inS p CR 1 1 =ω LD p CR 1 2 =ω ( )( )2 2 22 1 2 11 pp Dm in out Rg V V ωωωω ++ =
CH 11 Frequency Response 15 Pole Identification Example II in m S p C g R       = 1 || 1 1ω LD p CR 1 2 =ω
CH 11 Frequency Response 16 Circuit with Floating Capacitor  The pole of a circuit is computed by finding the effective resistance and capacitance from a node to GROUND.  The circuit above creates a problem since neither terminal of CF is grounded.
CH 11 Frequency Response 17 Miller’s Theorem  If Av is the gain from node 1 to 2, then a floating impedance ZF can be converted to two grounded impedances Z1 and Z2. v F A Z Z − = 1 1 v F A Z Z /11 2 − =
CH 11 Frequency Response 18 Miller Multiplication  With Miller’s theorem, we can separate the floating capacitor. However, the input capacitor is larger than the original floating capacitor. We call this Miller multiplication.
CH 11 Frequency Response 19 Example: Miller Theorem ( ) FDmS in CRgR + = 1 1 ω F Dm D out C Rg R       + = 1 1 1 ω
High-Pass Filter Response 12 1 2 1 2 1 11 + = ω ω CR CR V V in out  The voltage division between a resistor and a capacitor can be configured such that the gain at low frequency is reduced. CH 11 Frequency Response 20
Example: Audio Amplifier nFCi 6.79= nFCL 8.39=  In order to successfully pass audio band frequencies (20 Hz-20 KHz), large input and output capacitances are needed. Ω= Ω= 200/1 100 m i g KR CH 11 Frequency Response 21
Capacitive Coupling vs. Direct Coupling  Capacitive coupling, also known as AC coupling, passes AC signals from Y to X while blocking DC contents.  This technique allows independent bias conditions between stages. Direct coupling does not. Capacitive Coupling Direct Coupling CH 11 Frequency Response 22
Typical Frequency Response Lower Corner Upper Corner CH 11 Frequency Response 23
CH 11 Frequency Response 24 High-Frequency Bipolar Model  At high frequency, capacitive effects come into play. Cb represents the base charge, whereas Cµ and Cje are the junction capacitances. b jeC C Cπ = +
CH 11 Frequency Response 25 High-Frequency Model of Integrated Bipolar Transistor  Since an integrated bipolar circuit is fabricated on top of a substrate, another junction capacitance exists between the collector and substrate, namely CCS.
CH 11 Frequency Response 26 Example: Capacitance Identification
CH 11 Frequency Response 27 MOS Intrinsic Capacitances  For a MOS, there exist oxide capacitance from gate to channel, junction capacitances from source/drain to substrate, and overlap capacitance from gate to source/drain.
CH 11 Frequency Response 28 Gate Oxide Capacitance Partition and Full Model  The gate oxide capacitance is often partitioned between source and drain. In saturation, C2 ~ Cgate, and C1 ~ 0. They are in parallel with the overlap capacitance to form CGS and CGD.
CH 11 Frequency Response 29 Example: Capacitance Identification
CH 11 Frequency Response 30 Transit Frequency  Transit frequency, fT, is defined as the frequency where the current gain from input to output drops to 1. π π C g f m T =2 GS m T C g f =π2
Example: Transit Frequency Calculation ( )THGS n T VV L f −= 2 2 3 2 µ π GHzf sVcm mVVV nmL T n THGS 226 )./(400 100 65 2 = = =− = µ CH 11 Frequency Response 31
Analysis Summary  The frequency response refers to the magnitude of the transfer function.  Bode’s approximation simplifies the plotting of the frequency response if poles and zeros are known.  In general, it is possible to associate a pole with each node in the signal path.  Miller’s theorem helps to decompose floating capacitors into grounded elements.  Bipolar and MOS devices exhibit various capacitances that limit the speed of circuits. CH 11 Frequency Response 32
High Frequency Circuit Analysis Procedure  Determine which capacitor impact the low-frequency region of the response and calculate the low-frequency pole (neglect transistor capacitance).  Calculate the midband gain by replacing the capacitors with short circuits (neglect transistor capacitance).  Include transistor capacitances.  Merge capacitors connected to AC grounds and omit those that play no role in the circuit.  Determine the high-frequency poles and zeros.  Plot the frequency response using Bode’s rules or exact analysis. CH 11 Frequency Response 33
Frequency Response of CS Stage with Bypassed Degeneration ( ) ( ) 1 1 ++ +− = SmbS bSDm X out RgsCR sCRRg s V V  In order to increase the midband gain, a capacitor Cb is placed in parallel with Rs.  The pole frequency must be well below the lowest signal frequency to avoid the effect of degeneration. CH 11 Frequency Response 34
CH 11 Frequency Response 35 Unified Model for CE and CS Stages
CH 11 Frequency Response 36 Unified Model Using Miller’s Theorem
Example: CE Stage fFC fFC fFC mAI R CS C S 30 20 100 100 1 200 = = = = = Ω= µ π β ( ) ( )GHz MHz outp inp 59.12 5162 , , ×= ×= πω πω  The input pole is the bottleneck for speed. CH 11 Frequency Response 37
Example: Half Width CS Stage XW 2↓             ++ =             ++ = 2 2 1 2 1 22 1 2 1 , , XY Lm out L outp XYLmin S inp C Rg C R CRgC R ω ω CH 11 Frequency Response 38
CH 11 Frequency Response 39 Direct Analysis of CE and CS Stages  Direct analysis yields different pole locations and an extra zero. ( ) ( ) ( ) ( ) ( )outinXYoutXYinLThev outXYLinThevThevXYLm p outXYLinThevThevXYLm p XY m z CCCCCCRR CCRCRRCRg CCRCRRCRg C g ++ ++++ = ++++ = = 1 || 1 1 || || 2 1 ω ω ω
CH 11 Frequency Response 40 Example: CE and CS Direct Analysis ( )[ ] ( ) ( )[ ] ( ) ( )( )outinXYoutXYinOOS outXYOOinSSXYOOm p outXYOOinSSXYOOm p CCCCCCrrR CCrrCRRCrrg CCrrCRRCrrg ++ ++++ ≈ ++++ ≈ 21 21211 2 21211 1 || )(||||1 )(||||1 1 ω ω
Example: Comparison Between Different Methods ( ) ( )MHz MHz outp inp 4282 5712 , , ×= ×= πω πω ( ) ( )GHz MHz outp inp 53.42 2642 , , ×= ×= πω πω ( ) ( )GHz MHz outp inp 79.42 2492 , , ×= ×= πω πω ( ) Ω= = Ω= = = = Ω= − KR g fFC fFC fFC R L m DB GD GS S 2 0 150 100 80 250 200 1 λ Miller’s Exact Dominant Pole CH 11 Frequency Response 41
CH 11 Frequency Response 42 Input Impedance of CE and CS Stages ( )[ ] π µπ r sCRgC Z Cm in || 1 1 ++ ≈ ( )[ ]sCRgC Z GDDmGS in ++ ≈ 1 1
Low Frequency Response of CB and CG Stages ( ) ( ) miSm iCm in out gsCRg sCRg s V V ++ = 1  As with CE and CS stages, the use of capacitive coupling leads to low-frequency roll-off in CB and CG stages (although a CB stage is shown above, a CG stage is similar). CH 11 Frequency Response 43
CH 11 Frequency Response 44 Frequency Response of CB Stage X m S Xp C g R       = 1 || 1 ,ω πCCX = YL Yp CR 1 , =ω CSY CCC += µ ∞=Or
CH 11 Frequency Response 45 Frequency Response of CG Stage ∞=Or X m S Xp C g R       = 1 || 1 ,ω SBGSX CCC += YL Yp CR 1 , =ω DBGDY CCC +=  Similar to a CB stage, the input pole is on the order of fT, so rarely a speed bottleneck. ∞=Or
CH 11 Frequency Response 46 Example: CG Stage Pole Identification ( )11 1 , 1 || 1 GDSB m S Xp CC g R +      =ω ( )2211 2 , 1 1 DBGSGDDB m Yp CCCC g +++ =ω
Example: Frequency Response of CG Stage ( ) Ω= = Ω= = = = Ω= − KR g fFC fFC fFC R d m DB GD GS S 2 0 150 100 80 250 200 1 λ ( ) ( )MHz GHz Yp Xp 4422 31.52 , , ×= ×= πω πω CH 11 Frequency Response 47
CH 11 Frequency Response 48 Emitter and Source Followers  The following will discuss the frequency response of emitter and source followers using direct analysis.  Emitter follower is treated first and source follower is derived easily by allowing rπ to go to infinity.
CH 11 Frequency Response 49 Direct Analysis of Emitter Follower 1 1 2 ++ + = bsas s g C V V m in out π ( ) m LS m S LL m S g C r R g C CRb CCCCCC g R a       +++= ++= π π µ πµπµ 1
CH 11 Frequency Response 50 Direct Analysis of Source Follower Stage 1 1 2 ++ + = bsas s g C V V m GS in out ( ) m SBGD GDS SBGSSBGDGSGD m S g CC CRb CCCCCC g R a + += ++=
Example: Frequency Response of Source Follower ( ) 0 150 100 80 250 100 200 1 = Ω= = = = = Ω= − λ m DB GD GS L S g fFC fFC fFC fFC R ( )[ ] ( )[ ]GHzjGHz GHzjGHz p p 57.279.12 57.279.12 2 1 −−= +−= πω πω CH 11 Frequency Response 51
CH 11 Frequency Response 52 Example: Source Follower 1 1 2 ++ + = bsas s g C V V m GS in out [ ] 1 2211 1 2211111 1 ))(( m DBGDSBGD GDS DBGDSBGSGDGSGD m S g CCCC CRb CCCCCCC g R a +++ += ++++=
CH 11 Frequency Response 53 Input Capacitance of Emitter/Source Follower Lm GS GDin Rg CC CCC + += 1 / / π µ ∞=Or
CH 11 Frequency Response 54 Example: Source Follower Input Capacitance ( ) 1 211 1 ||1 1 GS OOm GDin C rrg CC + +=
CH 11 Frequency Response 55 Output Impedance of Emitter Follower 1++ ++ = βππ πππ sCr RrsCrR I V SS X X
CH 11 Frequency Response 56 Output Impedance of Source Follower mGS GSS X X gsC sCR I V + + = 1
CH 11 Frequency Response 57 Active Inductor  The plot above shows the output impedance of emitter and source followers. Since a follower’s primary duty is to lower the driving impedance (RS>1/gm), the “active inductor” characteristic on the right is usually observed.
CH 11 Frequency Response 58 Example: Output Impedance ( ) 33 321 1|| mGS GSOO X X gsC sCrr I V + + = ∞=Or
CH 11 Frequency Response 59 Frequency Response of Cascode Stage  For cascode stages, there are three poles and Miller multiplication is smaller than in the CE/CS stage. 1 2 1 , −≈ − = m m XYv g g A XYx CC 2≈
CH 11 Frequency Response 60 Poles of Bipolar Cascode ( )( )111 , 2|| 1 µππ ω CCrRS Xp + = ( )121 2 , 2 1 1 µπ ω CCC g CS m Yp ++ = ( )22 , 1 µ ω CCR CSL outp + =
CH 11 Frequency Response 61 Poles of MOS Cascode             ++ = 1 2 1 1 , 1 1 GD m m GSS Xp C g g CR ω             +++ = 1 1 2 21 2 , 1 1 1 GD m m GSDB m Yp C g g CC g ω ( )22 , 1 GDDBL outp CCR + =ω
Example: Frequency Response of Cascode ( ) Ω= = Ω= = = = Ω= − KR g fFC fFC fFC R L m DB GD GS S 2 0 150 100 80 250 200 1 λ ( ) ( ) ( )MHz GHz GHz outp Yp Xp 4422 73.12 95.12 , , , ×= ×= ×= πω πω πω CH 11 Frequency Response 62
CH 11 Frequency Response 63 MOS Cascode Example             ++ = 1 2 1 1 , 1 1 GD m m GSS Xp C g g CR ω       ++      +++ = 331 1 2 21 2 , 1 1 1 DBGDGD m m GSDB m Yp CCC g g CC g ω ( )22 , 1 GDDBL outp CCR + =ω
CH 11 Frequency Response 64 I/O Impedance of Bipolar Cascode ( )sCC rZin 11 1 2 1 || µπ π + = ( )sCC RZ CS Lout 22 1 || + = µ
CH 11 Frequency Response 65 I/O Impedance of MOS Cascode sC g g C Z GD m m GS in             ++ = 1 2 1 1 1 1 ( )sCC RZ DBGD Lout 22 1 || + =
CH 11 Frequency Response 66 Bipolar Differential Pair Frequency Response  Since bipolar differential pair can be analyzed using half- circuit, its transfer function, I/O impedances, locations of poles/zeros are the same as that of the half circuit’s. Half Circuit
CH 11 Frequency Response 67 MOS Differential Pair Frequency Response  Since MOS differential pair can be analyzed using half- circuit, its transfer function, I/O impedances, locations of poles/zeros are the same as that of the half circuit’s. Half Circuit
CH 11 Frequency Response 68 Example: MOS Differential Pair ( )33 , 1 1 3 31 3 , 1311 , 1 1 1 1 ])/1([ 1 GDDBL outp GD m m GSDB m Yp GDmmGSS Xp CCR C g g CC g CggCR + =             +++ = ++ = ω ω ω
Common Mode Frequency Response ( ) 12 1 ++ +∆ = ∆ ∆ SSmSSSS SSSSDm CM out RgsCR CRRg V V  Css will lower the total impedance between point P to ground at high frequency, leading to higher CM gain which degrades the CM rejection ratio. CH 11 Frequency Response 69
Tail Node Capacitance Contribution  Source-Body Capacitance of M1, M2 and M3  Gate-Drain Capacitance of M3 CH 11 Frequency Response 70
Example: Capacitive Coupling ( )[ ]EBin RrRR 1|| 222 ++= βπ ( ) ( )Hz CRr B L 5422 || 1 111 1 ×== πω π ( ) ( )Hz CRR inC L 9.22 1 22 2 ×= + = πω CH 11 Frequency Response 71
( ) ( )MHz CRR inD L 92.62 1 221 2 ×= + = πω ( )MHz CR Rg S Sm L 4.422 1 11 11 1 ×= + = πω 2 2 1 v F in A R R − = Example: IC Amplifier – Low Frequency Design CH 11 Frequency Response 72
( ) 77.3|| 211 −=−= inDm in X RRg v v Example: IC Amplifier – Midband Design CH 11 Frequency Response 73
Example: IC Amplifier – High Frequency Design )21.1(2 )15.1( 1 )15.2(2 )308(2 222 3 2 1 GHz CCR GHz MHz DBGDL p p p ×= + = ×= ×= π ω πω πω CH 11 Frequency Response 74

More Related Content

PPTX
Z Transform
byDarshan Bhatt
 
PPTX
Amplitude modulation & demodulation
byBikz013
 
PPT
Z Transform And Inverse Z Transform - Signal And Systems
byMr. RahüL YøGi
 
PPTX
Network synthesis
byMohammed Waris Senan
 
PPTX
ASk,FSK,PSK
byOla Mashaqi @ an-najah national university
 
PDF
Negative feedback Amplifiers
byYeshudas Muttu
 
PPT
Microwave components
byKannan Sridharan
 
DOCX
Double Side band Suppressed carrier (DSB-SC) Modulation and Demodulation.
bySAiFul IslAm
 
Z Transform
byDarshan Bhatt
 
Amplitude modulation & demodulation
byBikz013
 
Z Transform And Inverse Z Transform - Signal And Systems
byMr. RahüL YøGi
 
Network synthesis
byMohammed Waris Senan
 
ASk,FSK,PSK
byOla Mashaqi @ an-najah national university
 
Negative feedback Amplifiers
byYeshudas Muttu
 
Microwave components
byKannan Sridharan
 
Double Side band Suppressed carrier (DSB-SC) Modulation and Demodulation.
bySAiFul IslAm
 

What's hot

PPTX
Network Analysis and Synthesis
byPHI Learning Pvt. Ltd.
 
PDF
Hybrid Parameter in BJT
byRCC Institute of Information Technology
 
PPTX
Emitter Coupled Logic (ECL)
byshahin kadir
 
PPT
transmission-line-and-waveguide-ppt
byATTO RATHORE
 
PPTX
Unit-2 AC-DC converter
byjohny renoald
 
PPTX
M ary psk and m ary qam ppt
byDANISHAMIN950
 
PDF
Communication systems solution manual 5th edition
byTayeen Ahmed
 
PPTX
Basics of Oscillator
byhimanshi gupta
 
PPT
Filter design1
byMohamad Ariffin Mutalib
 
PPTX
Properties of fourier transform
byNisarg Amin
 
PDF
ANALOG TO DIGITAL CONVERTOR
byAnil Yadav
 
PPT
transmission-lines
byATTO RATHORE
 
PPTX
Topic 2 - Switch Realization.pptx
byVanJasperCastillo
 
PPTX
CMOS
byAWANISHKUMAR84
 
PPT
Feedback amplifiers
byForwardBlog Enewzletter
 
PDF
Design of FIR filters
byop205
 
PDF
Solved problems in waveguides
bysubhashinivec
 
PPTX
Fir filter design using windows
bySarang Joshi
 
PPT
Z transfrm ppt
bySWATI MISHRA
 
PPTX
Phase Shift Keying & π/4 -Quadrature Phase Shift Keying
byNaveen Jakhar, I.T.S
 
Network Analysis and Synthesis
byPHI Learning Pvt. Ltd.
 
Hybrid Parameter in BJT
byRCC Institute of Information Technology
 
Emitter Coupled Logic (ECL)
byshahin kadir
 
transmission-line-and-waveguide-ppt
byATTO RATHORE
 
Unit-2 AC-DC converter
byjohny renoald
 
M ary psk and m ary qam ppt
byDANISHAMIN950
 
Communication systems solution manual 5th edition
byTayeen Ahmed
 
Basics of Oscillator
byhimanshi gupta
 
Filter design1
byMohamad Ariffin Mutalib
 
Properties of fourier transform
byNisarg Amin
 
ANALOG TO DIGITAL CONVERTOR
byAnil Yadav
 
transmission-lines
byATTO RATHORE
 
Topic 2 - Switch Realization.pptx
byVanJasperCastillo
 
CMOS
byAWANISHKUMAR84
 
Feedback amplifiers
byForwardBlog Enewzletter
 
Design of FIR filters
byop205
 
Solved problems in waveguides
bysubhashinivec
 
Fir filter design using windows
bySarang Joshi
 
Z transfrm ppt
bySWATI MISHRA
 
Phase Shift Keying & π/4 -Quadrature Phase Shift Keying
byNaveen Jakhar, I.T.S
 

Viewers also liked

PPT
Frequency Response Analysis and Bode Diagrams for First Order Systems
byVishvaraj Chauhan
 
PPSX
Frequency response
byBambang Sujanarko
 
PPT
ppt on Time Domain and Frequency Domain Analysis
bysagar_kamble
 
PPTX
Chapter 4 time domain analysis
byBin Biny Bino
 
PPT
Bode plot
byshalini singh
 
PPTX
Chapter5
bySrinivas Naidu
 
PPTX
Bode diagram
byAbdurazak Mohamed
 
PDF
Bjt+and+jfet+frequency+response
byStudent
 
PDF
Amplifier frequency response(part 1)
byJamil Ahmed
 
PDF
Bode lect
byYogesh Verma
 
PDF
Circuit Network Analysis - [Chapter5] Transfer function, frequency response, ...
bySimen Li
 
PPT
Time response
bySarah Krystelle
 
PPT
Long-Latency Motor Evoked Potentials in Spinal Cord Injury
byDavid Barnkow, AuD, DABNM, CNIM, CCC/A
 
PPTX
Encoding of frequency and volley theory
byKemUnited
 
PPTX
Chapter 7
byMerce Tumibay
 
PPTX
Repetitive transcanial magnetic stimulation(r tms) for depression treatment
byGuru Prasath
 
DOC
Bode
bysaru062
 
PDF
Time domain specifications of second order system
bySyed Saeed
 
PPT
bode_plot By DEV
byDevchandra Thakur
 
PDF
Lecture 14 ME 176 7 Root Locus Technique
byLeonides De Ocampo
 
Frequency Response Analysis and Bode Diagrams for First Order Systems
byVishvaraj Chauhan
 
Frequency response
byBambang Sujanarko
 
ppt on Time Domain and Frequency Domain Analysis
bysagar_kamble
 
Chapter 4 time domain analysis
byBin Biny Bino
 
Bode plot
byshalini singh
 
Chapter5
bySrinivas Naidu
 
Bode diagram
byAbdurazak Mohamed
 
Bjt+and+jfet+frequency+response
byStudent
 
Amplifier frequency response(part 1)
byJamil Ahmed
 
Bode lect
byYogesh Verma
 
Circuit Network Analysis - [Chapter5] Transfer function, frequency response, ...
bySimen Li
 
Time response
bySarah Krystelle
 
Long-Latency Motor Evoked Potentials in Spinal Cord Injury
byDavid Barnkow, AuD, DABNM, CNIM, CCC/A
 
Encoding of frequency and volley theory
byKemUnited
 
Chapter 7
byMerce Tumibay
 
Repetitive transcanial magnetic stimulation(r tms) for depression treatment
byGuru Prasath
 
Bode
bysaru062
 
Time domain specifications of second order system
bySyed Saeed
 
bode_plot By DEV
byDevchandra Thakur
 
Lecture 14 ME 176 7 Root Locus Technique
byLeonides De Ocampo
 

Similar to Frequency response

PDF
Ch_electronics_electronicselectronics11.pdf
byFedrale
 
PPTX
Frequency Response of Amplifier Analog Electronics Engineering
byJanviPanwar6
 
PPT
Lecture 13
byPatel Jay
 
PDF
Frequency Response Presentation slides .pdf
byasaleh221020
 
PPTX
Analog Electronic Circuits - Module 3
byAravinda Koithyar
 
PDF
09 bjt & fet frequency response
byTony Mac Apple
 
PDF
3661.pdf
byTesfuFiseha1
 
PDF
Electronic devices-and-circuit-theory-10th-ed-boylestad-chapter-9
byShiwam Isrie
 
PPTX
lect_17_amplifier_frequency_response.pptx
byubhatt1
 
DOCX
Exp passive filter (6)
bySarah Krystelle
 
DOCX
Exp passive filter (4)
bySarah Krystelle
 
DOCX
Exp passive filter (1)
bySarah Krystelle
 
DOCX
Exp passive filter (5)
bySarah Krystelle
 
PPTX
Frequency Response.pptx
byDebasishMohanta16
 
DOCX
Exp passive filter (3)
bySarah Krystelle
 
DOCX
Exp passive filter (7)
bySarah Krystelle
 
PPTX
sp12Part2 CIRCUITS AND SYSTEMS FOR COMPUTER ENGINEERING .pptx
byElisée Ndjabu
 
PDF
Freq response of CE and CC discrete circuits
byJavaria Haseeb
 
DOCX
Exp passive filter (9)
bySarah Krystelle
 
DOCX
Exp1 (passive filter) agdon
bySarah Krystelle
 
Ch_electronics_electronicselectronics11.pdf
byFedrale
 
Frequency Response of Amplifier Analog Electronics Engineering
byJanviPanwar6
 
Lecture 13
byPatel Jay
 
Frequency Response Presentation slides .pdf
byasaleh221020
 
Analog Electronic Circuits - Module 3
byAravinda Koithyar
 
09 bjt & fet frequency response
byTony Mac Apple
 
3661.pdf
byTesfuFiseha1
 
Electronic devices-and-circuit-theory-10th-ed-boylestad-chapter-9
byShiwam Isrie
 
lect_17_amplifier_frequency_response.pptx
byubhatt1
 
Exp passive filter (6)
bySarah Krystelle
 
Exp passive filter (4)
bySarah Krystelle
 
Exp passive filter (1)
bySarah Krystelle
 
Exp passive filter (5)
bySarah Krystelle
 
Frequency Response.pptx
byDebasishMohanta16
 
Exp passive filter (3)
bySarah Krystelle
 
Exp passive filter (7)
bySarah Krystelle
 
sp12Part2 CIRCUITS AND SYSTEMS FOR COMPUTER ENGINEERING .pptx
byElisée Ndjabu
 
Freq response of CE and CC discrete circuits
byJavaria Haseeb
 
Exp passive filter (9)
bySarah Krystelle
 
Exp1 (passive filter) agdon
bySarah Krystelle
 

More from Patel Jay

PPT
digital logic_families
byPatel Jay
 
PPT
Introduction to electronic circuit design..model
byPatel Jay
 
PPT
operational amplifiers
byPatel Jay
 
PPT
operational amplifiers
byPatel Jay
 
PPT
logic_families
byPatel Jay
 
PPT
Logic families
byPatel Jay
 
PPT
Lesson 8 op amps
byPatel Jay
 
PPT
operational amplifiers
byPatel Jay
 
PPSX
Chapter 14 management strategies in an organization
byPatel Jay
 
PPSX
Chapter 13 management of organization function
byPatel Jay
 
PPSX
Chapter 12 new concepts and trends in management
byPatel Jay
 
PPSX
Chapter 11 controlling function of management
byPatel Jay
 
PPSX
Chapter 10 power,politics and authority
byPatel Jay
 
PPSX
Chapter 09 conflict,communication,and coordination
byPatel Jay
 
PPSX
Chapter 08 organizational change and stress management
byPatel Jay
 
PPSX
Chapter 07 groups and teams in an organization
byPatel Jay
 
PPSX
Chapter 06 leadership
byPatel Jay
 
PPSX
Chapter 05 MOTIVATION
byPatel Jay
 
PPSX
Chapter 04 Directing function of management
byPatel Jay
 
PPSX
Chapter 03 organization and organizing
byPatel Jay
 
digital logic_families
byPatel Jay
 
Introduction to electronic circuit design..model
byPatel Jay
 
operational amplifiers
byPatel Jay
 
operational amplifiers
byPatel Jay
 
logic_families
byPatel Jay
 
Logic families
byPatel Jay
 
Lesson 8 op amps
byPatel Jay
 
operational amplifiers
byPatel Jay
 
Chapter 14 management strategies in an organization
byPatel Jay
 
Chapter 13 management of organization function
byPatel Jay
 
Chapter 12 new concepts and trends in management
byPatel Jay
 
Chapter 11 controlling function of management
byPatel Jay
 
Chapter 10 power,politics and authority
byPatel Jay
 
Chapter 09 conflict,communication,and coordination
byPatel Jay
 
Chapter 08 organizational change and stress management
byPatel Jay
 
Chapter 07 groups and teams in an organization
byPatel Jay
 
Chapter 06 leadership
byPatel Jay
 
Chapter 05 MOTIVATION
byPatel Jay
 
Chapter 04 Directing function of management
byPatel Jay
 
Chapter 03 organization and organizing
byPatel Jay
 

Recently uploaded

PDF
DHA/HAAD/MOH/DOH OPTOMETRY MCQ PYQ. .pdf
byAnmol Singh
 
PPTX
Filipino 11-Tekstong Prosidyural-Final.pptx
byMargieBAlmoza
 
PDF
Projecte de la porta d'i5B: Els animals marins
byeduardrubio1
 
PPTX
Kochi MuleSoftMeetup_UnlockingMCPServer.pptx
bysandeepmenon62
 
PDF
Projecte de la porta de primer B: L'antic Egipte
byeduardrubio1
 
PDF
1ST APPLICATION FOR ANNULMENT (4)8787666.pdf
bykonstantinantountoum1
 
PPTX
How to use search_read method in Odoo 18
byCeline George
 
PDF
Models of Teaching - TNTEU - B.Ed I Semester - Teaching and Learning - BD1TL ...
byDr Raja Mohammed T
 
PDF
IMANI Africa files RTI request seeking full disclosure on 2026 SIM registrati...
bynservice241
 
PPTX
Searching in PubMed andCochrane_Practical Presentation.pptx
bySystematic Reviews Network (SRN)
 
PDF
Toward Massive, Ultrareliable, and Low-Latency Wireless Communication With Sh...
byMan_Ebook
 
PPTX
AI_in_Daily_Life_Presentation and more.pptx
bybantydansena
 
PDF
Unit-III pdf (Basic listening Skill, Effective Writing Communication & Writin...
bySayyadTarannum
 
PDF
Scalable-MADDPG-Based Cooperative Target Invasion for a Multi-USV System.pdf
byMan_Ebook
 
PPTX
ATTENTION -PART 2.pptx Shilpa Hotakar for I semester BSc students
bySHILPA HOTAKAR
 
PDF
Blood Group Incompatibility: Rh Factor and Erythroblastosis Fetalis
bySudhandraKarthi
 
PPTX
Pain. definition, causes, factor influencing pain & pain assessment.pptx
byPompi Begum
 
PPTX
10-12-2025 Francois Staring How can Researchers and Initial Teacher Educators...
byEduSkills OECD
 
PPTX
How to Manage Reception Report in Odoo 18 Inventory
byCeline George
 
PDF
BỘ TEST KIỂM TRA CUỐI HỌC KÌ 1 - TIẾNG ANH 6-7-8-9 GLOBAL SUCCESS - PHIÊN BẢN...
byNguyen Thanh Tu Collection
 
DHA/HAAD/MOH/DOH OPTOMETRY MCQ PYQ. .pdf
byAnmol Singh
 
Filipino 11-Tekstong Prosidyural-Final.pptx
byMargieBAlmoza
 
Projecte de la porta d'i5B: Els animals marins
byeduardrubio1
 
Kochi MuleSoftMeetup_UnlockingMCPServer.pptx
bysandeepmenon62
 
Projecte de la porta de primer B: L'antic Egipte
byeduardrubio1
 
1ST APPLICATION FOR ANNULMENT (4)8787666.pdf
bykonstantinantountoum1
 
How to use search_read method in Odoo 18
byCeline George
 
Models of Teaching - TNTEU - B.Ed I Semester - Teaching and Learning - BD1TL ...
byDr Raja Mohammed T
 
IMANI Africa files RTI request seeking full disclosure on 2026 SIM registrati...
bynservice241
 
Searching in PubMed andCochrane_Practical Presentation.pptx
bySystematic Reviews Network (SRN)
 
Toward Massive, Ultrareliable, and Low-Latency Wireless Communication With Sh...
byMan_Ebook
 
AI_in_Daily_Life_Presentation and more.pptx
bybantydansena
 
Unit-III pdf (Basic listening Skill, Effective Writing Communication & Writin...
bySayyadTarannum
 
Scalable-MADDPG-Based Cooperative Target Invasion for a Multi-USV System.pdf
byMan_Ebook
 
ATTENTION -PART 2.pptx Shilpa Hotakar for I semester BSc students
bySHILPA HOTAKAR
 
Blood Group Incompatibility: Rh Factor and Erythroblastosis Fetalis
bySudhandraKarthi
 
Pain. definition, causes, factor influencing pain & pain assessment.pptx
byPompi Begum
 
10-12-2025 Francois Staring How can Researchers and Initial Teacher Educators...
byEduSkills OECD
 
How to Manage Reception Report in Odoo 18 Inventory
byCeline George
 
BỘ TEST KIỂM TRA CUỐI HỌC KÌ 1 - TIẾNG ANH 6-7-8-9 GLOBAL SUCCESS - PHIÊN BẢN...
byNguyen Thanh Tu Collection
 

Frequency response

  • 1.
    Chapter 11 FrequencyResponse  11.1 Fundamental Concepts  11.2 High-Frequency Models of Transistors  11.3 Analysis Procedure  11.4 Frequency Response of CE and CS Stages  11.5 Frequency Response of CB and CG Stages  11.6 Frequency Response of Followers  11.7 Frequency Response of Cascode Stage  11.8 Frequency Response of Differential Pairs  11.9 Additional Examples 1
  • 2.
    Chapter Outline CH 11Frequency Response 2
  • 3.
    CH 11 FrequencyResponse 3 High Frequency Roll-off of Amplifier  As frequency of operation increases, the gain of amplifier decreases. This chapter analyzes this problem.
  • 4.
    Example: Human VoiceI  Natural human voice spans a frequency range from 20Hz to 20KHz, however conventional telephone system passes frequencies from 400Hz to 3.5KHz. Therefore phone conversation differs from face-to-face conversation. CH 11 Frequency Response 4 Natural Voice Telephone System
  • 5.
    Example: Human VoiceII CH 11 Frequency Response 5 Mouth RecorderAir Mouth EarAir Skull Path traveled by the human voice to the voice recorder Path traveled by the human voice to the human ear  Since the paths are different, the results will also be different.
  • 6.
    Example: Video Signal Video signals without sufficient bandwidth become fuzzy as they fail to abruptly change the contrast of pictures from complete white into complete black. CH 11 Frequency Response 6 High Bandwidth Low Bandwidth
  • 7.
    Gain Roll-off: SimpleLow-pass Filter  In this simple example, as frequency increases the impedance of C1 decreases and the voltage divider consists of C1 and R1 attenuates Vin to a greater extent at the output. CH 11 Frequency Response 7
  • 8.
    CH 11 FrequencyResponse 8 Gain Roll-off: Common Source  The capacitive load, CL, is the culprit for gain roll-off since at high frequency, it will “steal” away some signal current and shunt it to ground. 1 ||out m in D L V g V R C s   = −  ÷  
  • 9.
    CH 11 FrequencyResponse 9 Frequency Response of the CS Stage  At low frequency, the capacitor is effectively open and the gain is flat. As frequency increases, the capacitor tends to a short and the gain starts to decrease. A special frequency is ω=1/(RDCL), where the gain drops by 3dB. 1222 + = ωLD Dm in out CR Rg V V
  • 10.
    CH 11 FrequencyResponse 10 Example: Figure of Merit  This metric quantifies a circuit’s gain, bandwidth, and power dissipation. In the bipolar case, low temperature, supply, and load capacitance mark a superior figure of merit. LCCT CVV MOF 1 ... =
  • 11.
    Example: Relationship betweenFrequency Response and Step Response CH 11 Frequency Response 11 ( ) 2 2 2 1 1 1 1 H s j R C ω ω = = + ( ) ( )0 1 1 1 expout t V t V u t R C  − = − ÷    The relationship is such that as R1C1 increases, the bandwidth drops and the step response becomes slower.
  • 12.
    CH 11 FrequencyResponse 12 Bode Plot  When we hit a zero, ωzj, the Bode magnitude rises with a slope of +20dB/dec.  When we hit a pole, ωpj, the Bode magnitude falls with a slope of -20dB/dec           +        +       +      + = 21 21 0 11 11 )( pp zz ss ss AsH ωω ωω
  • 13.
    CH 11 FrequencyResponse 13 Example: Bode Plot  The circuit only has one pole (no zero) at 1/(RDCL), so the slope drops from 0 to -20dB/dec as we pass ωp1. LD p CR 1 1 =ω
  • 14.
    CH 11 FrequencyResponse 14 Pole Identification Example I inS p CR 1 1 =ω LD p CR 1 2 =ω ( )( )2 2 22 1 2 11 pp Dm in out Rg V V ωωωω ++ =
  • 15.
    CH 11 FrequencyResponse 15 Pole Identification Example II in m S p C g R       = 1 || 1 1ω LD p CR 1 2 =ω
  • 16.
    CH 11 FrequencyResponse 16 Circuit with Floating Capacitor  The pole of a circuit is computed by finding the effective resistance and capacitance from a node to GROUND.  The circuit above creates a problem since neither terminal of CF is grounded.
  • 17.
    CH 11 FrequencyResponse 17 Miller’s Theorem  If Av is the gain from node 1 to 2, then a floating impedance ZF can be converted to two grounded impedances Z1 and Z2. v F A Z Z − = 1 1 v F A Z Z /11 2 − =
  • 18.
    CH 11 FrequencyResponse 18 Miller Multiplication  With Miller’s theorem, we can separate the floating capacitor. However, the input capacitor is larger than the original floating capacitor. We call this Miller multiplication.
  • 19.
    CH 11 FrequencyResponse 19 Example: Miller Theorem ( ) FDmS in CRgR + = 1 1 ω F Dm D out C Rg R       + = 1 1 1 ω
  • 20.
    High-Pass Filter Response 12 1 2 1 2 1 11 + = ω ω CR CR V V in out The voltage division between a resistor and a capacitor can be configured such that the gain at low frequency is reduced. CH 11 Frequency Response 20
  • 21.
    Example: Audio Amplifier nFCi6.79= nFCL 8.39=  In order to successfully pass audio band frequencies (20 Hz-20 KHz), large input and output capacitances are needed. Ω= Ω= 200/1 100 m i g KR CH 11 Frequency Response 21
  • 22.
    Capacitive Coupling vs.Direct Coupling  Capacitive coupling, also known as AC coupling, passes AC signals from Y to X while blocking DC contents.  This technique allows independent bias conditions between stages. Direct coupling does not. Capacitive Coupling Direct Coupling CH 11 Frequency Response 22
  • 23.
    Typical Frequency Response LowerCorner Upper Corner CH 11 Frequency Response 23
  • 24.
    CH 11 FrequencyResponse 24 High-Frequency Bipolar Model  At high frequency, capacitive effects come into play. Cb represents the base charge, whereas Cµ and Cje are the junction capacitances. b jeC C Cπ = +
  • 25.
    CH 11 FrequencyResponse 25 High-Frequency Model of Integrated Bipolar Transistor  Since an integrated bipolar circuit is fabricated on top of a substrate, another junction capacitance exists between the collector and substrate, namely CCS.
  • 26.
    CH 11 FrequencyResponse 26 Example: Capacitance Identification
  • 27.
    CH 11 FrequencyResponse 27 MOS Intrinsic Capacitances  For a MOS, there exist oxide capacitance from gate to channel, junction capacitances from source/drain to substrate, and overlap capacitance from gate to source/drain.
  • 28.
    CH 11 FrequencyResponse 28 Gate Oxide Capacitance Partition and Full Model  The gate oxide capacitance is often partitioned between source and drain. In saturation, C2 ~ Cgate, and C1 ~ 0. They are in parallel with the overlap capacitance to form CGS and CGD.
  • 29.
    CH 11 FrequencyResponse 29 Example: Capacitance Identification
  • 30.
    CH 11 FrequencyResponse 30 Transit Frequency  Transit frequency, fT, is defined as the frequency where the current gain from input to output drops to 1. π π C g f m T =2 GS m T C g f =π2
  • 31.
    Example: Transit FrequencyCalculation ( )THGS n T VV L f −= 2 2 3 2 µ π GHzf sVcm mVVV nmL T n THGS 226 )./(400 100 65 2 = = =− = µ CH 11 Frequency Response 31
  • 32.
    Analysis Summary  Thefrequency response refers to the magnitude of the transfer function.  Bode’s approximation simplifies the plotting of the frequency response if poles and zeros are known.  In general, it is possible to associate a pole with each node in the signal path.  Miller’s theorem helps to decompose floating capacitors into grounded elements.  Bipolar and MOS devices exhibit various capacitances that limit the speed of circuits. CH 11 Frequency Response 32
  • 33.
    High Frequency CircuitAnalysis Procedure  Determine which capacitor impact the low-frequency region of the response and calculate the low-frequency pole (neglect transistor capacitance).  Calculate the midband gain by replacing the capacitors with short circuits (neglect transistor capacitance).  Include transistor capacitances.  Merge capacitors connected to AC grounds and omit those that play no role in the circuit.  Determine the high-frequency poles and zeros.  Plot the frequency response using Bode’s rules or exact analysis. CH 11 Frequency Response 33
  • 34.
    Frequency Response ofCS Stage with Bypassed Degeneration ( ) ( ) 1 1 ++ +− = SmbS bSDm X out RgsCR sCRRg s V V  In order to increase the midband gain, a capacitor Cb is placed in parallel with Rs.  The pole frequency must be well below the lowest signal frequency to avoid the effect of degeneration. CH 11 Frequency Response 34
  • 35.
    CH 11 FrequencyResponse 35 Unified Model for CE and CS Stages
  • 36.
    CH 11 FrequencyResponse 36 Unified Model Using Miller’s Theorem
  • 37.
    Example: CE Stage fFC fFC fFC mAI R CS C S 30 20 100 100 1 200 = = = = = Ω= µ π β () ( )GHz MHz outp inp 59.12 5162 , , ×= ×= πω πω  The input pole is the bottleneck for speed. CH 11 Frequency Response 37
  • 38.
    Example: Half WidthCS Stage XW 2↓             ++ =             ++ = 2 2 1 2 1 22 1 2 1 , , XY Lm out L outp XYLmin S inp C Rg C R CRgC R ω ω CH 11 Frequency Response 38
  • 39.
    CH 11 FrequencyResponse 39 Direct Analysis of CE and CS Stages  Direct analysis yields different pole locations and an extra zero. ( ) ( ) ( ) ( ) ( )outinXYoutXYinLThev outXYLinThevThevXYLm p outXYLinThevThevXYLm p XY m z CCCCCCRR CCRCRRCRg CCRCRRCRg C g ++ ++++ = ++++ = = 1 || 1 1 || || 2 1 ω ω ω
  • 40.
    CH 11 FrequencyResponse 40 Example: CE and CS Direct Analysis ( )[ ] ( ) ( )[ ] ( ) ( )( )outinXYoutXYinOOS outXYOOinSSXYOOm p outXYOOinSSXYOOm p CCCCCCrrR CCrrCRRCrrg CCrrCRRCrrg ++ ++++ ≈ ++++ ≈ 21 21211 2 21211 1 || )(||||1 )(||||1 1 ω ω
  • 41.
    Example: Comparison BetweenDifferent Methods ( ) ( )MHz MHz outp inp 4282 5712 , , ×= ×= πω πω ( ) ( )GHz MHz outp inp 53.42 2642 , , ×= ×= πω πω ( ) ( )GHz MHz outp inp 79.42 2492 , , ×= ×= πω πω ( ) Ω= = Ω= = = = Ω= − KR g fFC fFC fFC R L m DB GD GS S 2 0 150 100 80 250 200 1 λ Miller’s Exact Dominant Pole CH 11 Frequency Response 41
  • 42.
    CH 11 FrequencyResponse 42 Input Impedance of CE and CS Stages ( )[ ] π µπ r sCRgC Z Cm in || 1 1 ++ ≈ ( )[ ]sCRgC Z GDDmGS in ++ ≈ 1 1
  • 43.
    Low Frequency Responseof CB and CG Stages ( ) ( ) miSm iCm in out gsCRg sCRg s V V ++ = 1  As with CE and CS stages, the use of capacitive coupling leads to low-frequency roll-off in CB and CG stages (although a CB stage is shown above, a CG stage is similar). CH 11 Frequency Response 43
  • 44.
    CH 11 FrequencyResponse 44 Frequency Response of CB Stage X m S Xp C g R       = 1 || 1 ,ω πCCX = YL Yp CR 1 , =ω CSY CCC += µ ∞=Or
  • 45.
    CH 11 FrequencyResponse 45 Frequency Response of CG Stage ∞=Or X m S Xp C g R       = 1 || 1 ,ω SBGSX CCC += YL Yp CR 1 , =ω DBGDY CCC +=  Similar to a CB stage, the input pole is on the order of fT, so rarely a speed bottleneck. ∞=Or
  • 46.
    CH 11 FrequencyResponse 46 Example: CG Stage Pole Identification ( )11 1 , 1 || 1 GDSB m S Xp CC g R +      =ω ( )2211 2 , 1 1 DBGSGDDB m Yp CCCC g +++ =ω
  • 47.
    Example: Frequency Responseof CG Stage ( ) Ω= = Ω= = = = Ω= − KR g fFC fFC fFC R d m DB GD GS S 2 0 150 100 80 250 200 1 λ ( ) ( )MHz GHz Yp Xp 4422 31.52 , , ×= ×= πω πω CH 11 Frequency Response 47
  • 48.
    CH 11 FrequencyResponse 48 Emitter and Source Followers  The following will discuss the frequency response of emitter and source followers using direct analysis.  Emitter follower is treated first and source follower is derived easily by allowing rπ to go to infinity.
  • 49.
    CH 11 FrequencyResponse 49 Direct Analysis of Emitter Follower 1 1 2 ++ + = bsas s g C V V m in out π ( ) m LS m S LL m S g C r R g C CRb CCCCCC g R a       +++= ++= π π µ πµπµ 1
  • 50.
    CH 11 FrequencyResponse 50 Direct Analysis of Source Follower Stage 1 1 2 ++ + = bsas s g C V V m GS in out ( ) m SBGD GDS SBGSSBGDGSGD m S g CC CRb CCCCCC g R a + += ++=
  • 51.
    Example: Frequency Responseof Source Follower ( ) 0 150 100 80 250 100 200 1 = Ω= = = = = Ω= − λ m DB GD GS L S g fFC fFC fFC fFC R ( )[ ] ( )[ ]GHzjGHz GHzjGHz p p 57.279.12 57.279.12 2 1 −−= +−= πω πω CH 11 Frequency Response 51
  • 52.
    CH 11 FrequencyResponse 52 Example: Source Follower 1 1 2 ++ + = bsas s g C V V m GS in out [ ] 1 2211 1 2211111 1 ))(( m DBGDSBGD GDS DBGDSBGSGDGSGD m S g CCCC CRb CCCCCCC g R a +++ += ++++=
  • 53.
    CH 11 FrequencyResponse 53 Input Capacitance of Emitter/Source Follower Lm GS GDin Rg CC CCC + += 1 / / π µ ∞=Or
  • 54.
    CH 11 FrequencyResponse 54 Example: Source Follower Input Capacitance ( ) 1 211 1 ||1 1 GS OOm GDin C rrg CC + +=
  • 55.
    CH 11 FrequencyResponse 55 Output Impedance of Emitter Follower 1++ ++ = βππ πππ sCr RrsCrR I V SS X X
  • 56.
    CH 11 FrequencyResponse 56 Output Impedance of Source Follower mGS GSS X X gsC sCR I V + + = 1
  • 57.
    CH 11 FrequencyResponse 57 Active Inductor  The plot above shows the output impedance of emitter and source followers. Since a follower’s primary duty is to lower the driving impedance (RS>1/gm), the “active inductor” characteristic on the right is usually observed.
  • 58.
    CH 11 FrequencyResponse 58 Example: Output Impedance ( ) 33 321 1|| mGS GSOO X X gsC sCrr I V + + = ∞=Or
  • 59.
    CH 11 FrequencyResponse 59 Frequency Response of Cascode Stage  For cascode stages, there are three poles and Miller multiplication is smaller than in the CE/CS stage. 1 2 1 , −≈ − = m m XYv g g A XYx CC 2≈
  • 60.
    CH 11 FrequencyResponse 60 Poles of Bipolar Cascode ( )( )111 , 2|| 1 µππ ω CCrRS Xp + = ( )121 2 , 2 1 1 µπ ω CCC g CS m Yp ++ = ( )22 , 1 µ ω CCR CSL outp + =
  • 61.
    CH 11 FrequencyResponse 61 Poles of MOS Cascode             ++ = 1 2 1 1 , 1 1 GD m m GSS Xp C g g CR ω             +++ = 1 1 2 21 2 , 1 1 1 GD m m GSDB m Yp C g g CC g ω ( )22 , 1 GDDBL outp CCR + =ω
  • 62.
    Example: Frequency Responseof Cascode ( ) Ω= = Ω= = = = Ω= − KR g fFC fFC fFC R L m DB GD GS S 2 0 150 100 80 250 200 1 λ ( ) ( ) ( )MHz GHz GHz outp Yp Xp 4422 73.12 95.12 , , , ×= ×= ×= πω πω πω CH 11 Frequency Response 62
  • 63.
    CH 11 FrequencyResponse 63 MOS Cascode Example             ++ = 1 2 1 1 , 1 1 GD m m GSS Xp C g g CR ω       ++      +++ = 331 1 2 21 2 , 1 1 1 DBGDGD m m GSDB m Yp CCC g g CC g ω ( )22 , 1 GDDBL outp CCR + =ω
  • 64.
    CH 11 FrequencyResponse 64 I/O Impedance of Bipolar Cascode ( )sCC rZin 11 1 2 1 || µπ π + = ( )sCC RZ CS Lout 22 1 || + = µ
  • 65.
    CH 11 FrequencyResponse 65 I/O Impedance of MOS Cascode sC g g C Z GD m m GS in             ++ = 1 2 1 1 1 1 ( )sCC RZ DBGD Lout 22 1 || + =
  • 66.
    CH 11 FrequencyResponse 66 Bipolar Differential Pair Frequency Response  Since bipolar differential pair can be analyzed using half- circuit, its transfer function, I/O impedances, locations of poles/zeros are the same as that of the half circuit’s. Half Circuit
  • 67.
    CH 11 FrequencyResponse 67 MOS Differential Pair Frequency Response  Since MOS differential pair can be analyzed using half- circuit, its transfer function, I/O impedances, locations of poles/zeros are the same as that of the half circuit’s. Half Circuit
  • 68.
    CH 11 FrequencyResponse 68 Example: MOS Differential Pair ( )33 , 1 1 3 31 3 , 1311 , 1 1 1 1 ])/1([ 1 GDDBL outp GD m m GSDB m Yp GDmmGSS Xp CCR C g g CC g CggCR + =             +++ = ++ = ω ω ω
  • 69.
    Common Mode FrequencyResponse ( ) 12 1 ++ +∆ = ∆ ∆ SSmSSSS SSSSDm CM out RgsCR CRRg V V  Css will lower the total impedance between point P to ground at high frequency, leading to higher CM gain which degrades the CM rejection ratio. CH 11 Frequency Response 69
  • 70.
    Tail Node CapacitanceContribution  Source-Body Capacitance of M1, M2 and M3  Gate-Drain Capacitance of M3 CH 11 Frequency Response 70
  • 71.
    Example: Capacitive Coupling ()[ ]EBin RrRR 1|| 222 ++= βπ ( ) ( )Hz CRr B L 5422 || 1 111 1 ×== πω π ( ) ( )Hz CRR inC L 9.22 1 22 2 ×= + = πω CH 11 Frequency Response 71
  • 72.
    ( ) ( )MHz CRRinD L 92.62 1 221 2 ×= + = πω ( )MHz CR Rg S Sm L 4.422 1 11 11 1 ×= + = πω 2 2 1 v F in A R R − = Example: IC Amplifier – Low Frequency Design CH 11 Frequency Response 72
  • 73.
    ( ) 77.3||211 −=−= inDm in X RRg v v Example: IC Amplifier – Midband Design CH 11 Frequency Response 73
  • 74.
    Example: IC Amplifier– High Frequency Design )21.1(2 )15.1( 1 )15.2(2 )308(2 222 3 2 1 GHz CCR GHz MHz DBGDL p p p ×= + = ×= ×= π ω πω πω CH 11 Frequency Response 74