1. Teaching Electronic Circuits Top-Down and Bottom-Up Tamara A. Papalias EE Dept – E365 San Jose State University San Jose, CA

2. 2 Outline Motivation Op Amp Block Diagram Bias Block 2:1 Block Gain Block Output Buffer Block Benefits Summary

3. 3 Motivation Teach Students Circuit Theory Analysis and Design Teach Context of Structures Teach Design Trade-offs No “right” answer, just optimized Encourage Application Mindset Provide Roadmap for Sedra & Smith

4. 4 Op Amp Block Diagram

5. 5 Bias Block Bias 2:1 A Buffer Design Parameters I out vs. I in Output Resistance (R out ) Minimum Output Voltage (V omin ) Topics and Techniques Current Mirror Current Scaling Multiple Mirrors Transistor Sizing (BJT=area, MOS=W/L) Bandgap Topologies Simple Widlar Wilson Cascode

6. 6 2:1 Block Bias 2:1 A Buffer Topics and Techniques Differential pair ½ circuit model Active loads Clipping A DM vs. A CM Design Parameters Differential Gain (A DM ) Common-Mode Rejection Ratio (CMRR) Bias Levels Output Swing/Headroom

7. 7 Gain Block Bias 2:1 A Buffer Topics and Techniques Bode Plot Pole/Zero Identification & Analysis Miller Effect (Dominant Pole Approx.) Compensation Capacitor Negative Feedback Control Loop Shunt/Series Connections Design Parameters Gain Bandwidth Stability Gain Margin/Phase Margin

8. 8 Output Buffer Block Bias 2:1 A Buffer Topics and Techniques Amplifier classes (A, B, C, D) V out vs. V in graph Crossover Distortion Clipping Short-Circuit Protection Effects of Loading (R & C) Design Parameters Linearity Efficiency (  ) Slew Rate

9. 9 Summary BLOCKSPICEPRIMARY LESSON Bias.op Operating Point, References 2:1.tranSmall-Signal Analysis A.acFrequency Response Output Buffer.dcLarge Signal Analysis

10. 10 Benefits Bipolar and MOS can be taught side-by-side Adds to discussion of trade-offs Students begin to understand “good enough” Students identify interaction b/tn blocks Ex: How Rout of Bias sets CMRR with 2:1 block Can assign design projects of complete or partial op amp for specific applications Natural fit with SPICE commands Students retain “big picture”

11. 11 Feedback Thank you Any questions? Personal note: Students seem more engaged. Some cultures have harder time adjusting to trade-off method instead of “exact answer”