MSICT – RF Communication SoC

1. POWER OPTIMIZED LCVCO & MIXER CO-DESIGN Daniel Götz, Milosz Sroka June 20th, 2006 MSICT – RF Communication SoC

2. PAPER’S IMPLEMENTATION OUR IMPLEMENTATION RESULTS CONCLUSION INTRODUCTION • Power Optimized LC VCO & Mixer Co-design: • by Byunghoo Jung, Shubha Bommalingaiahnapallya, and Ramesh Harjani University of Minnesota, Dept. of ECE • Capacitively source degenerated buffer used as a negative resistance cell • No need of cross-coupled scheme • Reduced power consumption • Mixer input capacitance incorporated into the degeneration capacitor

3. INTRO OUR IMPLEMENTATION RESULTS CONCLUSION PAPER’S IMPLEMENTATION • General implementation steps (1): • LC Tank-based VCO Design Parallel LC oscillator model Parallel LC oscillator model Requirements of negative resistance Requirements of negative resistance Buffer sizing and parameters calculation Buffer sizing and parameters calculation Tank design for oscillation frequency Tank design for oscillation frequency Design of the VCO complete structure

4. INTRO OUR IMPLEMENTATION RESULTS CONCLUSION PAPER’S IMPLEMENTATION • General implementation steps (2): • Mixer Design  Standard Gilbert cell design  Reduced noise figure, maximized conversion gain  Input impedance characteristics • VCO-Mixer Co-Design  Incorporation of the mixer input impedance to the VCO structure.  Other linkage effects

5. INTRO PAPER’S IMPLEMENTATION RESULTS CONCLUSION OUR IMPLEMENTATION • Step 1/6: Tank design • Estimation of the oscillation frequency  L, C  • Calculation of the parasitic resistance of L  Graphically:  Approximation: • Required negative resistancefor compensation  Req

6. INTRO PAPER’S IMPLEMENTATION RESULTS CONCLUSION OUR IMPLEMENTATION • Step 2/6: “Degenerated Negative Resistance Cell” • Dimensioning of the degenerating cell  Cs, width, Ibias, VDD

7. INTRO PAPER’S IMPLEMENTATION RESULTS CONCLUSION OUR IMPLEMENTATION • Step 3/6: Tank Re-design • Calculation of the Ceq of the cell • Re-design

8. INTRO PAPER’S IMPLEMENTATION RESULTS CONCLUSION OUR IMPLEMENTATION • Step 4/6: Oscillation structure • Tank biasing • Pulse generation

9. INTRO PAPER’S IMPLEMENTATION RESULTS CONCLUSION OUR IMPLEMENTATION • Step 5/6: Mixer design • Standard Gilbert cell  Transistor dimensioning  R load  I bias • Input impedance  R in series with C

10. INTRO PAPER’S IMPLEMENTATION RESULTS CONCLUSION OUR IMPLEMENTATION Step 5/6: Mixer design

11. INTRO PAPER’S IMPLEMENTATION RESULTS CONCLUSION OUR IMPLEMENTATION • Step 6/6: Co-design • Linkage  Mixer input impedance  Tank tuning (not necessary)  Linkage capacitance to eliminate DC offset

12. INTRO PAPER’S IMPLEMENTATION RESULTS CONCLUSION OUR IMPLEMENTATION Step 6/6: Co-design

13. INTRO PAPER’S IMPLEMENTATION RESULTS CONCLUSION OUR IMPLEMENTATION Step 6/6: Co-design

14. INTRO PAPER’S IMPLEMENTATION OUR IMPLEMENTATION CONCLUSION RESULTS VCO Transient analysis: Single ended Differential output

15. INTRO PAPER’S IMPLEMENTATION OUR IMPLEMENTATION CONCLUSION RESULTS PSS and Pnoise analysis:

16. INTRO PAPER’S IMPLEMENTATION OUR IMPLEMENTATION RESULTS CONCLUSION • Comparison between paper and our implementation: • Low power design could not be achieved because of, • Different Technology (paper = 0.18µm, used = 0.35µm) • Not sufficient good inductors (Q, parasitic resistance) • comparable PSS results • Phase noise was realized not that good as in the paper. At 1GHz paper = -107dBc/Hz; our implementation = -52dBc/Hz • Discovered Bottleneck of this design: • Inductors; because provide mainly the parasitic resistance which should be compensated with the Buffer-Transistors.