1. Differential Amplifiers Prof. Paul Hasler

2. Differential Transistor Pairs MOSFET Diff-PairBJT Diff-Pair

3. Differential Transistor Pairs MOSFET Diff-PairBJT Diff-Pair The bottom transistor (the one with I bias ) sets the total current

4. Differential Transistor Pairs MOSFET Diff-PairBJT Diff-Pair The bottom transistor (the one with I bias ) sets the total current The upper two transistors compete for a fraction of this current

5. Analysis of Diff-Pair

10. Source of Common-Mode Gain

11. Analysis of Diff-Pair

13. Differential Pair Currents -0.4 3 2 100.10.20.30.4 0 0.5 1 1.5 2 2.5 3 Differential input voltage (V) Output current (nA) I out + I out -

14. Transistor ‘Leg’ Currents

16. BJT Differential Pair Analysis V1V1 V2V2 VbVb GND I out +-

17. BJT Differential Amplifier V1V1 V2V2 VbVb GND I out +-

18. BJT Differential Amplifier V1V1 V2V2 VbVb GND V dd V out I out

19. BJT Differential Amplifier V1V1 V2V2 VbVb GND Fixed output voltage: Current output Zero output current: Voltage output V dd V out I out

20. Basic Differential Amplifier

21. Transfer Functions

22. Wide-Output Range Differential Amplifier Simple differential amplifer "Vmin" effect

23. Wide-Output Range Differential Amplifier Wide-output range amplifier Simple differential amplifer "Vmin" effect

24. Wide-Output Range Differential Amplifier Wide-output range amplifier Simple differential amplifer "Vmin" effect

25. A Unity-Gain Follower

27. A more ideal Follower / Buffer Circuit Amp Gain = A v Solving: V out = V in AvAv 1 + A v

28. A Unity-Gain Follower Amp Gain = A v Solving: V out ~ V in

29. A Unity-Gain Follower Amp Gain = A v Solving: V out ~ V in

30. Differential Pairs / Amplifiers Differential Transistor Pairs Differential Amplifiers Unity-Gain Amplifiers