TABLE OF CONTENTS Page ABSTRACT . iii DEDICATION . v ACKNOWLEDGEMENTS . vi TABLE OF CONTENTS . vii LIST OF FIGURES . ix LIST OF TABLES . xiii CHAPTER I INTRODUCTION 1 II BASIC VGA STRUCTURES . 4 II.1 VGA structures . 4 II.1.1 Differential pair with diode-connected loads . 4 II.1.2 Analog multiplier . 12 II.1.3 Differential pair with source degeneration . 16 II.1.4 Complementary differential pairs with source degeneration . 17 II.2 Comparison of the commonly used VGA structures 20 III PROGRAMMABLE CURRENT MIRROR 22 III.1 Review of simple current mirror 22 III.2 Proposed programmable current mirror 24 III.2.1 AC response of programmable current mirror 29 III.2.2 Programmability of the programmable current mirror . 35 III.3 Conclusions . 36 IV DESIGN CONSIDERATIONS OF THE PROPOSED VGA 38 IV.1 VGA design challenges and motivations 38 IV.2 System-level overview of the proposed VGA s 39 IV.2.1 System-level design of the proposed VGA 39 IV.2.2 Introduction of the building blocks of the proposed VGA 40 IV.3 Detailed discussion of the VGA building blocks 43 CHAPTER Page IV.3.1 Gain control scheme . 43 IV.3.2 Input stage complementary differential pairs with source degeneration . 47 IV.3.3 Current gain stage—programmable current mirror 49 IV.3.4 Frequency compensation scheme . 51 IV.3.5 DC offset cancellation 57 IV.3.6 Digital control circuit 57 IV.3.7 The dimension and bias current for the VGA . 58 IV.4 Conclusion . 59 V SUMMARY OF RESULTS . 60 V.1 Design summary . 60 V.2 Simulation setup . 60 V.3 Simulation results . 63 V.3.1 Explanation of simulation terminologies . 63 V.3.2 Layout 67 V.3.3 AC response . 68 V.3.4 Noise 73 V.3.5 Linearity . 75 V.3.6 Power consumption 77 V.4 Experimental results . 77 V.4.1 Experimental results for the AC response of the VGA 79 V.4.2 Experimental results of the IIP3 . 86 V.4.3 Noise characterization 88 V.5 Summary of results and comparison 92 VI CONCLUSION . 95 REFERENCES 97 APPENDIX A . 99 APPENDIX B 102 VITA 107
