1. DESIGN of ANALOG FILTERS Rolf Schaumann/Haiqiao Xiao/ Copyright © 2010 by Oxford University Press, Inc. Mac E. Van Valkenburg C H A P T E R 2 OPERATIONAL AMPLIFIERS

2. DESIGN of ANALOG FILTERS Rolf Schaumann/Haiqiao Xiao/ Copyright © 2010 by Oxford University Press, Inc. Mac E. Van Valkenburg Figure 2.1 Operational amplifier. All voltages are referred to the 0-V ground terminals. Inputs and output usually have a common ground terminal as indicated in b.

3. DESIGN of ANALOG FILTERS Rolf Schaumann/Haiqiao Xiao/ Copyright © 2010 by Oxford University Press, Inc. Mac E. Van Valkenburg Figure 2.2 The operational amplifier. (a) Diagram of a bipolar circuit showing the three main signal blocks, g m, −A 2, and a unity-gain buffer;

4. DESIGN of ANALOG FILTERS Rolf Schaumann/Haiqiao Xiao/ Copyright © 2010 by Oxford University Press, Inc. Mac E. Van Valkenburg Figure 2.2 (b) single-opamp package with pin configurations; (c) external circuitry, most notably power supplies.

5. DESIGN of ANALOG FILTERS Rolf Schaumann/Haiqiao Xiao/ Copyright © 2010 by Oxford University Press, Inc. Mac E. Van Valkenburg Figure 2.3 Functional parts of an opamp.

6. DESIGN of ANALOG FILTERS Rolf Schaumann/Haiqiao Xiao/ Copyright © 2010 by Oxford University Press, Inc. Mac E. Van Valkenburg Figure 2.4 Frequency response of a real opamp. (a) Magnitude and phase of the LM741; (b) gain and phase responses of a high-frequency opamp (OPA300).

7. DESIGN of ANALOG FILTERS Rolf Schaumann/Haiqiao Xiao/ Copyright © 2010 by Oxford University Press, Inc. Mac E. Van Valkenburg Figure 2.4Continued

8. DESIGN of ANALOG FILTERS Rolf Schaumann/Haiqiao Xiao/ Copyright © 2010 by Oxford University Press, Inc. Mac E. Van Valkenburg Figure 2.5 (a) Opamp model withfinite input and output resistors and a controlled voltage source of gain A(s); (b) opamp symbol.

9. DESIGN of ANALOG FILTERS Rolf Schaumann/Haiqiao Xiao/ Copyright © 2010 by Oxford University Press, Inc. Mac E. Van Valkenburg Figure 2.6 Model (a) and symbol (b) of an ideal opamp.

10. DESIGN of ANALOG FILTERS Rolf Schaumann/Haiqiao Xiao/ Copyright © 2010 by Oxford University Press, Inc. Mac E. Van Valkenburg