1. Project Bighorn: A CMOS Low Pass Switched-Capacitor Filter
Authors
Brien Bliatout
DeMarcus Levy
Samuel Russum
Advisor
Dr. Peter Osterberg
Industry Representative
Mr. Michael Desmith
Intel
Founders Day, 2005
University of Portland School of Engineering

2. Special Thanks Dr. Osterberg – Ideas & Guidance
Mr. Desmith – Ideas & Guidance
Andrew Hui – Debugging & Ideas
Sandy Ressel – Parts
Dr. Lu – 555 Chip & Delay Line
MEP (MOSIS Educational Program)
Founders Day, 2005
University of Portland School of Engineering

3. Agenda Introduction DeMarcus Background Brien Methods Sam
Results DeMarcus/Sam
Conclusions DeMarcus
Demonstration
Founders Day, 2005
University of Portland School of Engineering

4. What is Project Bighorn?
Low Pass Switched-Capacitor Filter (LPSCF)
Purpose:
Analog amplifiers are large
Resistors
IC Implementation Plausible
Filter Bandwidth Variation
Accuracy
Founders Day, 2005
University of Portland School of Engineering

5. Importance Dr. Osterberg EE 451 Class Demonstration
1st Switched-Capacitor Filter (SCF) at UP
Founders Day, 2005
University of Portland School of Engineering

6. What You Will Learn Switched-Capacitor (SC) Component vs. Resistor SCF
Founders Day, 2005
University of Portland School of Engineering

7. General 1st Order Filter
Background
General 1st Order Filter R2
-R2 (1 + C1R1s)
R1 (1 + C2R2s)
T(s) = R1
Founders Day, 2005
University of Portland School of Engineering

8. SC Equivalent of a Resistor1 =
fsC1
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University of Portland School of Engineering

9. General 1st Order SCF Founders Day, 2005
University of Portland School of Engineering

10. Bighorn 1st Order LPSCF Founders Day, 2005
University of Portland School of Engineering

11. Ideal Clock Signals fs = 17 kHz Founders Day, 2005
University of Portland School of Engineering

12. Frequency Response Founders Day, 2005
University of Portland School of Engineering

13. Ideal System Response Gain = -10 V/V = +20dB -3dB point = 186 Hz
Band Pass = 180o
-3dB = 137o
Founders Day, 2005
University of Portland School of Engineering

14. S and Z Domain Relation
fs >> fi T(z) can be represented as continuous
-R2
ωH = 1/(R2CA)
fH = 1/(2πR2CA)
T(s) =
R1 (1+ R2CAs)
1/(fsC2)
R1 =
1/(fsC3)
R2 =
-C2
ωH = fsC2/(CA)
fH = fsC2/(2πCA)
T(s) =
C3 [1+ CA/(fsC2) s]
Founders Day, 2005
University of Portland School of Engineering

15. Methods Waterfall Method Founders Day, 2005
University of Portland School of Engineering

16. Results Block Diagram Founders Day, 2005
University of Portland School of Engineering

17. Bighorn LPSCF Founders Day, 2005
University of Portland School of Engineering

18. 555 Schematic Founders Day, 2005
University of Portland School of Engineering

19. Φ2 Clock Signal Founders Day, 2005
University of Portland School of Engineering

20. Delay Line Founders Day, 2005
University of Portland School of Engineering

21. Ideal Clock Signals Founders Day, 2005
University of Portland School of Engineering

22. Macro Model SCF Founders Day, 2005
University of Portland School of Engineering

23. MOSIS Layout Founders Day, 2005
University of Portland School of Engineering

24. MOSIS Layout Close-up Founders Day, 2005
University of Portland School of Engineering

25. Final Product Founders Day, 2005
University of Portland School of Engineering

26. MOSIS Chip Faults Founders Day, 2005
University of Portland School of Engineering

27. Conclusion SCF Definition Why SCF? L-Edit Considerations
Bottom Line: 1st SCF at UP & Demo Vehicle
Founders Day, 2005
University of Portland School of Engineering

28. Demonstration Input Signal Output Signal—Shows Gain
-3db point—Shows Filtering
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University of Portland School of Engineering

29. Demonstration Founders Day, 2005
University of Portland School of Engineering

30. Any Questions? Thank You! Founders Day, 2005
University of Portland School of Engineering