1. Oscillator Circuits

2. Outline Oscillators – Inverter-Based Oscillator – Introduction of Phase Noise Simulation – LC-Tank Based Oscillator Laplace Analysis Circuit Implementation Quality Factor Analysis

3. Inverter-Based Oscillator

4. Delay Per Stage of the Inverter (273 pS) (395 ps) Period: 395-273=122 pS, Delay per stage (T D ): 234-214=20 pS. Period is 2NT D

5. Oscillation Frequency Calculation f osc =2.14 GHz T osc =467 pS=2NT D – T D =20 pS – N=T osc /(2T D )=467 pS/(2 20)=11.68 – N must be odd. – Choose N as 11.

6. 11 Stage Oscillator

7. Period: 1.501 nS-1.052 nS=0.449 nS, Freq=2.227 GHz

8. Phase Noise

9. Periodic Steady State Analysis

10. Harmonics

11. Pnoise

12. Phase Noise of a Ring Oscillator

13. LC Tank Oscillator

14. Laplace Transform Analysis

15. LC Tank Oscillator Resonant Frequency: 2.14 GHz L=1 nH C=5.53 pF (Adjustable)

16. LC Tank Oscillator

17. Transient Simulation (Steady state after 10 nS) Frequency: 1.941GHz

18. Reduce the Value of Capacitor (2.16 GHz)

19. PSS and Pnoise Setting

20. Phase Noise

21. Quality Factor of 10 for the inductor Oscillation dies out since g tank is greater than g m of the transistor.

22. R ind =100 mΩ This is the maximum parasitic resistance we can have without destroying the oscillation.

23. Transient Simulation

24. Phase Noise with R ind =100 mΩ Even a little series resistance at unreasonably high Q (130) can degrade phase noise quickly.