Session 8 Low Noise Amplifier Design 1 Introduction

Introduction of Noise (A)High Frequency Noise 1. Thermal (Johnson or Nyquist) noise 1. Thermal

Noise Factor and Noise Figure of Amplifier Si So=G·Si Ni No=G·Ni+ N Si= Input

Noise Figure of a Two-Port Networks Noise Parameters: (4 values) Fmin : Minimum noise

Noise Parameters of the Transistor Ga. As FET ATF-10136 Noise Parameters Frequency dependent 中華大學電機系

Noise Parameters from Linear Model Touchstone-format S-parameters with noise data ! SIEMENS Discrete &

Noise Parameters from Nonlinear Model Nonlinear Transistor Model Determine Biasing Circuits Small Signal Analysis

Constant Noise Figure Circles of Transistor Let F= Fi Fmin è| S- CFi| =

Constant Noise Figure Circles of Transistor rn越大，當遠離 min時 NF上升越快。 NFmin-2 d. B NFmin-3 d.

Noise Circles v. s. Available Gain Circles Trade-off is needed! NF min 兼顧NF and

Inductor Series Feedback Method BFP 420 (IC=1. 5 m. A, VCE=1 V) @ f=2

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Session 8 Low Noise Amplifier Design 1

Introduction of Noise (A)High Frequency Noise 1. Thermal (Johnson or Nyquist) noise 1. Thermal vibration of bound charges. 2. Shot noise Random fluctuations of charge carriers. (B)Low Frequency Noise Flicker (1/f) noise Noise power varies inversely with frequency. LNA cares high frequency noise only! 中華大學電機系田慶誠 2

Noise Factor and Noise Figure of Amplifier Si So=G·Si Ni No=G·Ni+ N Si= Input signal power So= Output signal power Ni= Standard input thermal noise No= Total output noise power N= Amplifier excess noise power G= Amplifier power gain Noise factor Noise figure (Ni=k. T 0 B=-174 d. Bm/Hz+Bandwidth(d. BHz) @ T=T 0=290°K) 中華大學電機系田慶誠 3

Noise Figure of a Two-Port Networks Noise Parameters: (4 values) Fmin : Minimum noise factor @ S= min rn= Rn/Z 0 : Normalized noise resistance min=| min| qmin Minimum-noise source reflection coefficient @ F= Fmin 中華大學電機系田慶誠 4

Noise Parameters of the Transistor Ga. As FET ATF-10136 Noise Parameters Frequency dependent 中華大學電機系田慶誠 Bias dependent 5

Noise Parameters from Linear Model Touchstone-format S-parameters with noise data ! SIEMENS Discrete & RF Semiconductors ! ! BFP 420 ! f ! Si NPN RF SIEGET Grounded Emitter Transistor in SOT 343 ! GHz ! VCE = 1 V IC = 1. 5 m. A ! Common Emitter S-Parameters: February 1998 # GHz S MA R 50 ! f S 11 ! GHz MAG ANG S 21 S 12 MAG ANG S 22 MAG ANG 0. 010 0. 9253 -0. 9 5. 283 179. 7 0. 0013 94. 7 0. 9962 -0. 5 0. 100 0. 9234 -7. 4 5. 274 174. 7 0. 0117 85. 7 0. 9935 -4. 1 1. 000 0. 8120 -72. 4 4. 363 126. 8 0. 0972 48. 1 0. 8140 -37. 3 Fmin Gammaopt rn/50 d. B MAG ANG - 0. 450 0. 71 0. 32 21 0. 35 0. 900 0. 76 0. 51 34 0. 27 1. 800 1. 07 0. 36 78 0. 20 2. 400 1. 17 0. 36 97 0. 19 3. 000 1. 43 0. 37 132 0. 12 4. 000 1. 70 0. 41 -173 0. 09 ! ! SIEMENS AG Semiconductor Group, Munich 2. 000 0. 6826 -129. 4 3. 080 88. 7 0. 1318 21. 7 0. 5819 -60. 9 3. 000 0. 6464 -171. 6 2. 264 61. 1 0. 1373 6. 7 0. 4292 -76. 2 4. 000 0. 6509 155. 6 1. 748 38. 1 0. 1339 -2. 2 0. 3584 -96. 2 5. 000 0. 6888 132. 5 1. 389 18. 6 0. 1269 -7. 3 0. 3011 -115. 3 6. 000 0. 7115 116. 0 1. 148 中華大學電機系田慶誠 1. 5 0. 1241 -7. 7 0. 3095 -142. 2 6

Noise Parameters from Nonlinear Model Nonlinear Transistor Model Determine Biasing Circuits Small Signal Analysis Noise measurements Optimum Noise Figure Match: GMN Minimum Noise Figure: NFMin Noise Resistance: RN 通常其結果準確度不一定足夠，僅供設計時參考！中華大學電機系田慶誠 7

Constant Noise Figure Circles of Transistor Let F= Fi Fmin è| S- CFi| = r. Fi 為 S-Plane上的圓方程式，並稱之為constant noise figure circle 半徑圓心 where 中華大學電機系田慶誠 8

Constant Noise Figure Circles of Transistor rn越大，當遠離 min時 NF上升越快。 NFmin-2 d. B NFmin-3 d. B NFmin-1 d. B NFmin S-Plane 中華大學電機系田慶誠 9

Noise Circles v. s. Available Gain Circles Trade-off is needed! NF min 兼顧NF and GA 亦即兼顧VSWR 1 中華大學電機系田慶誠 GA MS S-Plane 10

Inductor Series Feedback Method BFP 420 (IC=1. 5 m. A, VCE=1 V) @ f=2 GHz Stabilizing load Emitter feedback inductor 中華大學電機系田慶誠 11