CMOS Optical Preamplifier Design Using Graphical Circuit Analysis

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I n2 : I n2b : I n3 and I n3b : 5.2 Developing an Analytic <strong>Circuit</strong> Model 120 low frequencies. The effective cancellation of noise in this configuration has also been described in terms of a recirculation of the noise current within the cascode transistor [Buchwald,1995]. i scA This noise source is already input-referred, so = . This noise current, like the positive component of , is injected into node , making its input-referred contribution From the relation in Equation (5.20), we see that for much of the passband, (5.20) so that noise currents injected into node A are essentially input-referred. In other words, node A is practically identical to the input node from a noise perspective. From a small-signal standpoint, current sources and are identical, and we can analyze them together. Since these noise currents are injected directly into the output port, we can determine an expression for their input-referred equivalent values as a product of their effect on the output voltage and the transimpedance gain: 2 I n3( b)in 2 sCin + gm1 + g 2 s1 2 = ------------------------------------------- I n2b = + I n2bin = i in v out g m1 v out -------- × ----------- i scout 2 × g s1 2 I n3( b) 2 I n2bin ≈ 2 I n2b 1 ⎛vout⎞ ⎜-------- ⎟ ⎝ ⎠ 1 – ≈ ( s) i in 2 I n2in g m1 2 I n2 I n1 sC in + ------------------------ + I n3 s = 0 × g s1 I n3b Z out( s) 2 2 I n2b 2 × 2 I n3( b) (5.21)
5.2 Developing an Analytic <strong>Circuit</strong> Model 121 Our approximation of the transimpedance term using the dc value is justified because we are only interested in the input-referred noise spectrum within the passband where the transimpedance term lies within 3dB of the dc value. To determine the output impedance of the preamplifier, Z out( s) , we can follow the same proce- dure that we used to derive a first-order model for the input impedance. The process of making successive approximations and collapsing the SFG is illustrated in Figure 5.13. Similar to our earlier analysis of the input impedance, we have been able to use DPI/SFG analysis to simplify the port impedance down to a simple RCnetwork as shown in Figure 5.14. As expected, resistance component of the first-order model is simply the output resistance calculated in Chapter 3 and given in Equation (3.18). We are now in a position to compute the input-referred equivalent of noise sources I n3 and : Rout = 1 ⁄ gm2 + R f ------------------------------ 1 + K cm K cm = gm3 ⁄ gm2 C L Z out Figure 5.14 First-order model of the preamplifier output impedance. I n3b 2 I n3( b)in = ⎛vout⎞ ⎜-------- ⎟ ⎝ ⎠ 1 – i in s = 0 × Z out( s) 2 × 2 I n3( b) = 1 + K cm 1 ⁄ gm2 + R f 1 ---------------------------------------- × ------------------------------ × ------------------------------ 1 ⁄ gm2 – K cmR f 1 + K cm 1 + sRoutC L ⎛ 1 ⁄ gm2 + R f ⎞ ⎜---------------------------------------- ⎟ ⎝1⁄ gm2 – K cmR f ⎠ 2 1 ------------------------------ 1 + sRoutC L 2 = × 2 × I n3( b) 2 × 2 I n3( b) (5.22)
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CMOS Optical Preamplifier Design Us
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To achieve low-voltage operation, w
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Table of Contents CHAPTER 1 INTRODU
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CHAPTER 1 1.1 OVERVIEW Introduction
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Information Source Modulator Drive
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1.2 Thesis Outline 5 [Ohhata,1999].
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1.2 Thesis Outline 7 technique call
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1.2 Thesis Outline 9 Detector in St
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E e + - V bias 2.1 Photodetectors 1
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Diode Capacitance (pF) Diode capaci
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2.2 Optical Preamplifier Structures
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2.3 Transimpedance Amplifier Design
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I dc 2.3 Transimpedance Amplifier D
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Source Figure 2.11 General structur
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A = = For = 1V , the solution is v
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The gain of the forward amplifier c
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Feedback Analysis Using Return Rati
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2.4 Circuit Analysis Techniques 33
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2.5 An Overview of Signal-Flow Grap
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1 x1 x2 2.5 An Overview of Signal-F
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2.6 SUMMARY REFERENCES • ∆ k =
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Symp. Circuits Systems, vol. 3, pp.
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CHAPTER 3 New Transimpedance Amplif
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3.1 A Differential Transimpedance A
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3.2 A Feedback Topology for Ambient
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3.2 A Feedback Topology for Ambient
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Transimpedance (dBΩ) 90 80 60 40
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3.3 A Low-Voltage Transimpedance Am
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C 3 Φ1VB M 3 V B- =0.7V M 7 Figure
Page 75 and 76: 3.3 A Low-Voltage Transimpedance Am
Page 77 and 78: 3.4 SUMMARY 3.4 Summary 71 In this
Page 79 and 80: 3.4 Summary 73 Y. Nakagome et al.,
Page 81 and 82: 4.1 Introduction 75 back topology o
Page 83 and 84: 4.2 Circuit Analysis Using Driving-
Page 91 and 92: 4.3 DPI/SFG: Combining DPI Analysis
Page 93 and 94: 4.4 Determining Port Impedances 87
Page 95 and 96: v i R in v o R out 4.4 Determining
Page 97 and 98: id » ro and 1 ⁄ rid « Av ⁄ ro
Page 103 and 104: Z b r e g m 4.5 Analyzing Transisto
Page 105 and 106: 4.5 Analyzing Transistor Circuits 9
Page 107 and 108: Figure 4.25 SFG for the source foll
Page 115 and 116: 5.1 Analysis of the Low-Voltage Tra
Page 117 and 118: 5.1 Analysis of the Low-Voltage Tra
Page 119 and 120: 5.2 DEVELOPING AN ANALYTIC CIRCUIT
Page 121 and 122: Z in 5.2 Developing an Analytic Cir
Page 123 and 124: 5.2 Developing an Analytic Circuit
Page 125: I n1 : i in I n2 -I n1 i scin ( sCi
Page 129 and 130: I nRf : 5.2 Developing an Analytic
Page 131 and 132: DC transimpedance gain: Pole locati
Page 133 and 134: Frequency (MHz) 500 450 400 350 300
Page 135 and 136: Pole frequencies(MHz) 500 450 400 3
Page 137 and 138: Optimizing Sensitivity 5.2 Developi
Page 139 and 140: 5.2 Developing an Analytic Circuit
Page 141 and 142: Transimpedance Volts dB (lin) Gain
Page 143 and 144: CHAPTER 6 Implementation and Experi
Page 145 and 146: 6.1 A 1V Optical Receiver Front-End
Page 149 and 150: 6.1.2 Experimental Results 6.1 A 1V
Page 151 and 152: Gain(dB) 0 −1 −2 −3 −4 −5
Page 159 and 160: Clock signal of voltage doubler Eye
Page 161 and 162: 6.2 Variable-Gain Transimpedance Am
Page 163 and 164: 6.2.2 Experimental Results 6.2 Vari
Page 165 and 166: 6.3 Summary and State-of-the-Art Co
Page 167 and 168: Reference Outputs Technology Supply
Page 169 and 170: CHAPTER 7 Conclusions 7.1 SUMMARY A
Page 171 and 172: 7.2 Future Work 165 The significanc
Page 173 and 174: 7.2 Future Work 167 supply and subs
Page 175 and 176: v s i ti that part of the SFG for Q
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Thus, P1 ′ = b = 500Ω ∆1 ′
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itive representation of circuit dyn
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Bipolar Transistor i scb Z b v b b
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CMOS Optical Preamplifier Design Using Graphical Circuit Analysis

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