Ultra low-power low-noise amplifier designs for 2.4 GHz ISM band applications Tran Thi Thu Nga School of Electrical & Electronic Engineering A thesis submitted to the Nanyang Technological University in fulfillment of the requirement for the degree of Doctor Philosophy of Engineering July 2012 I STATEMENT OF ORIGINALITY I hereby certify the content of this thesis is the result of work done by me and has not been submitted for higher degree to any other University or Institution. Date Tran Thi Thu Nga II ABSTRACT The wireless communication industry is currently experiencing tremendous growth. In responding to the demand for a low-cost but high performance wireless front-end, many intensive researches on CMOS radio-frequency (RF) front-end circuits have been carried out. The ultimate goal is to minimize the trade-off between high performance and low-cost, low power consumption design. Low noise amplifier (LNA) is typically the first stage of a receiver. Its performance greatly affects the overall receiver performance. In this thesis, four LNAs are proposed. They are designed for the IEEE 802.15.4 standard in the 2.4 GHz ISM band. The first three LNAs are optimized for low NF and low power. An application of this type of LNA is to be used as the amplification stage before the active mixer in the receiver chain . Active mixer provides active gain while consuming some dc power. Therefore the LNA's gain requirement can be relaxed. But its power consumption needs to be low to compensate for the power consumption from the active mixer. With a relaxed gain, the LNA should have good NF to avoid degrading the overall receiver NF. The fourth LNA is optimized for high gain. This optimization is useful in the receiver system where passive mixer is used for frequency conversion. Passive mixer consumes no dc power while having some conversion loss. Therefore, high LNA gain is required in this type of system. There are four important contributions in this research. Firstly, and LNA (LNA1) that combining the merits of the inductive source degeneration common-source LNA (L-CSLNA) and the common-gate LNA (CGLNA) is introduced. The proposed LNA1 is a fully differential -boosting CGLNA with series inductor input matching network that I improves the NF. The circuit's input matching, NF and gain have been derived to verify the design methodology. The LNA was designed and fabricated using 0.18 µm CMOS technology. It consumes only 0.98 mA from 1.0 V power supply and achieves a measured gain of 15 dB and NF of 5 dB. The series inductor input matching CGLNA is attractive for low-power fully integrated applications in CMOS technologies. Even though the high NF problem of the CGLNA has been addressed in the proposed LNA1, we wish to further reduce the NF to achieve better trade-off between NF and power consumption. LNA2 was designed with a simple but effective noise-reducing technique. An inductor was added in parallel to the input transistor to reduce the noise from both the cascode and the input transistor. The LNA's input matching, NF and gain have been derived to verify the design methodology. The LNA achieves a measured gain of 14.8 dB, NF of 4.5 dB and IIP3 of -5.7dBm respectively. It consumes only 0.95 mW from a 1.0 V supply voltage. The third LNA (LNA3) was designed to consume less power and provide lower NF than that of LNA1 and LNA2. The power consumption can be reduce by operating the circuit at lower supply voltage but this shouldn't degrade the circuit's performance. LNA3 was designed for very low supply voltage such as 0.6 V. To deal with the small voltage headroom, the single-stage non-cascode structure is employed. The poor reverse isolation problem in this structure is improved by using the capacitive cross-coupling (CCC) across the two sides of a differential input stage. The CCC technique has been utilized in many LNA designs. However, in all of the reported works using CCC, the CCC technique was mainly used to improve the NF, not the reverse isolation. The poor reverse isolation problem in single-stage non-cascode structure has never been analyzed. This work shows II a novel analysis on the feedback cancellation mechanism to improve the reverse isolation. Other analysis on input matching, gain and NF of LNA3 was also performed to show the feasibility of employing CCC technique for low-voltage LNA as well as the advantages of LNA3 over the conventional common-source (CS) and common-gate (CG) LNA. This LNA is designed using 0.18 µm CMOS technology. At 2.4 GHz, high reverse isolation of -38 dB and good input matching of -24 dB was obtained. The LNA produces a total gain of 14 dB while drawing only 0.83 mA from a 0.6 V supply voltage. The NF is only 3.55 dB. The total power consumption is only 0.5 mW. The fourth LNA (LNA4) was designed to achieve very high gain. It utilizes the π- match and capacitive feedback input network. The capacitive feedback helps to eliminate the need of using inductor at the source terminal of the input transistor for input matching condition. Moreover, higher gain and an additional degree of design freedom are achieved with the use of the π-match network. The detailed input matching, NF and gain have been derived to verify the design methodology. The LNA is designed using 0.13µm RF CMOS technology. It achieves a gain of 21.7 dB with an S of -12 dB while 11 consuming only 0.6 mW. The NF is 4.9 dB and the IIP3 is -12 dBm. The performance of the four LNAs meets the specification requirements of the desired standard. In brief, the thesis investigates the CMOS RFIC designs, especially for LNA designs. It provides different approaches which can help to achieve a compact, low power and fully-integrated LNA. III ACKNOWLEDGEMENT During the long journey towards this doctoral degree, it would never be possible to come up with this dissertation and all the work that went into it, without the generous assistance and support of many great people. First and foremost, I would like to thank my supervisor, Professor Boon Chirn Chye, for his support over the whole research process. His advices on technical matters are invaluable, and his guidance is very critical for the successful of my research. Professor Boon‟s patience in answering questions and instruction of writing papers are greatly appreciated. I am greatly indebted and respectful to Professor Do Manh Anh and Professor Yeo Kiat Seng for their encourages and supports. I‟d like to thank Mr. Lim Wei Meng and my seniors, Aaron Do, Luo Sha, Ali Meaamar and Krishna Vamshi for their help in all of my designs, fabrications and measurements. Finally, I'd like to express my heartfelt thanks to my father, Tran Quang Hien, my mother, Pham Thi Tan, my sister, Tran Thi Quynh Nhu and my friend, Lim Y Hao, who have always encourage and support me. Despite many up-and-downs in my life, they are always there for me. Without their encouragement and inspiration, I would not have been the person who I am today. IV TABLE OF CONTENTS Abstract ........................................................................................................................... I Acknowledgement ......................................................................................................... IV TABLE OF CONTENTS ............................................................................................... V LIST OF FIGURES .................................................................................................... VIII LIST OF TABLES ........................................................................................................ XI 1. Chapter 1: Introduction ............................................................................................ 1 1.1 Motivation......................................................................................................... 1 1.2 Objective and Major contributions..................................................................... 2 1.3 Thesis organization ........................................................................................... 4 2. Chapter 2: Literature review on LNA design ............................................................ 5 2.1 Receiver architectures ....................................................................................... 5 2.1.1 Heterodyne Receiver .................................................................................. 5 2.1.2 Homodyne Receiver (Direct conversion receiver)....................................... 7 2.2 Design parameters ............................................................................................. 9 2.2.1 Sensitivity .................................................................................................. 9 2.2.2 Noise figure ............................................................................................... 9 2.2.3 Harmonic distortion and Intermodulation ................................................. 12 2.2.4 Dynamic Range ........................................................................................ 17 2.2.5 S-Parameters ............................................................................................ 18 2.3 Introduction to LNA ........................................................................................ 20 2.3.1 Performance trade-offs in LNA design ..................................................... 22 2.3.2 Input Architecture .................................................................................... 29 2.3.3 Tuning techniques of LNA's Load ............................................................ 40 V 2.3.4 Ultra-low power LNA design ................................................................... 44 2.3.5 IEEE 802.15.4 Specifications ................................................................... 45 3. Chapter 3: LNA1-Series input resonance common-gate LNA .............................. 47 3.1 The proposed series input resonance CGLNA (LNA1) .................................... 47 3.1.1 Input matching ......................................................................................... 47 3.1.2 Noise analysis .......................................................................................... 50 3.1.3 Circuit implementation ............................................................................. 53 3.2 Measurement results and discussion ................................................................ 57 3.3 Conclusion ...................................................................................................... 63 4. Chapter 4: LNA2- A noise reducing technique for common-gate LNA using shunt inductor ......................................................................................................................... 64 4.1 Noise analysis ................................................................................................. 64 4.1.1 Conventional non-cascode CGLNA ......................................................... 64 4.1.2 Conventional cascode CGLNA ................................................................ 65 4.1.3 The proposed LNA with noise reduction .................................................. 67 4.2 Circuit implementation .................................................................................... 71 4.3 Circuit performance and discussion ................................................................. 72 4.4 Conclusion ...................................................................................................... 75 5. Chapter 5: LNA3- Ultra-low power CMOS LNA with capacitive cross-coupling technique ....................................................................................................................... 76 5.1 Circuit description ........................................................................................... 77 5.2 Performance analysis ....................................................................................... 79 5.2.1 Reverse isolation ...................................................................................... 79 5.2.2 Noise........................................................................................................ 83 5.2.3 Gain and input matching .......................................................................... 86 5.3 Circuit Implementation .................................................................................... 89 VI 5.4 Measurement results and discussions ............................................................... 90 5.5 Conclusion ...................................................................................................... 95 6. Chapter 6: LNA4- A high gain LNA utilizing π-match and capacitive feedback input network .............................................................. .............................................................96 6.1 Extended noise analysis of the inductive source-degeneration common-source LNA (L-CSLNA)...........................................................................................................97 6.2 Proposed capacitive feedback CSLNA with π-match network (LNA4) ............ 99 6.3 Circuit implementation .................................................................................. 105 6.4 Measurement results and discussion .............................................................. 106 6.5 Conclusion .................................................................................................... 109 7. Chapter 7: Conclusion and future works ............................................................... 111 7.1 Conclusion .................................................................................................... 111 7.2 Future works ................................................................................................. 113 8. Author‟s Publications ........................................................................................... 115 9. APPENDIX.......................................................................................................... 116 APPENDIX A ............................................................................................................. 116 APPENDIX B ............................................................................................................. 122 APPENDIX C ............................................................................................................. 124 APPENDIX D ............................................................................................................. 128 REFERENCES............................................................................................................ 132 VII LIST OF FIGURES Figure 1.1 RF receiver ..................................................................................................... 1 Figure 2.1 Heterodyne receiver architecture..................................................................... 5 Figure 2.2: Rejection of image versus suppression of interferers for (a) high IF and (b) low IF.............................................................................................................................. 6 Figure 2.3: Dual-IF receiver ............................................................................................ 7 Figure 2.4 Homodyne receiver architecture ..................................................................... 8 Figure 2.5 Illustrations of P and IP (logarithmic scale)............................................. 13 1dB 3 Figure 2.6 Intermodulation in a nonlinear system .......................................................... 14 Figure 2.7 Corruption of a signal due to intermodulation between two interferers .......... 15 Figure 2.8 Dynamic ranges for a receiver ...................................................................... 18 Figure 2.9 A two-port network ...................................................................................... 19 Figure 2.10 Measurement of S-parameters using (a) matched output port, (b) matched input port ....................................................................................................................... 20 Figure 2.11: Important features in LNA design .............................................................. 22 Figure 2.12: Variation of I and g /I with V in CSM 0.18 µm RF CMOS technology ds m DS GS (W=120 µm) ................................................................................................................. 24 Figure 2.13: NMOS transconductance characteristics (GF 0.18 µm CMOS process, W/L=120/0.18, V =1 V) .............................................................................................. 26 DS Figure 2.14: |g /g | vs. V (GF 0.18 um CMOS process, W/L=120/0.18, V =1 V) ....... 27 1 3 GS DS Figure 2.15: Receiver's NF vs LNA's gain (IEEE 802.15.4 standard) ............................. 28 Figure 2.16: Receiver's IIP3 vs LNA's gain (IEEE 802.15.4 standard) ........................... 28 Figure 2.17 Common-source with resistive termination ................................................. 29 Figure 2.18: CGLNA ..................................................................................................... 31 Figure 2.19 Noise and signal voltage at the source and drain terminal of CGLNA ......... 34 Figure 2.20: (a) Single and (b) Differential CGLNA with noise cancellation ................. 35 Figure 2.21 Common-source input stage with shunt feedback ........................................ 36 Figure 2.22 Common-source input stage with source inductive degeneration ................. 38 Figure 2.23: NF of L-CSLNA vs L ..... 40 g Figure 2.24: LNA with resistive load ............................................................................. 41 VIII