Module 2: The Operational Amplifiers PDF

Module 2 The Operational Amplifiers 1–2 Op-Amp Input Modes and Parameters  1–1 Introduction to Operational Amplifiers 1–2 Op-Amp Input Modes and Parameters 1–3 Negative Feedback Chapter 1–4 Op-Amps with Negative Feedback 1–5 Effects of Negative Feedback on...

Module 2 The Operational Amplifiers 1–2 Op-Amp Input Modes and Parameters  1–1 Introduction to Operational Amplifiers 1–2 Op-Amp Input Modes and Parameters 1–3 Negative Feedback Chapter 1–4 Op-Amps with Negative Feedback 1–5 Effects of Negative Feedback on Op-Amp Impedances Outline 1–6 Bias Current and Offset Voltage 1–7 Open-Loop Frequency and Phase Responses 1–8 Closed-Loop Frequency Response 1–9 Troubleshooting Application Activity Programmable Analog Technology  Describe the basic operational amplifier and its characteristics Discuss op-amp modes and several parameters Explain negative feedback in op-amps Analyze op-amps with negative feedback Objectives Describe how negative feedback affects op-amp impedances Discuss bias current and offset voltage Analyze the open-loop frequency response of an op- amp Analyze the closed-loop frequency response of an op- amp Troubleshoot op-amp circuits  ✓Operational amplifier (op-amp) ✓ Differential amplifier ✓ Differential mode ✓ Common mode Key ✓ CMRR ✓ Open-loop voltage gain ✓ Slew rate ✓ Negative feedback Words ✓ Closed-loop voltage gain ✓ Noninverting amplifier ✓ Voltage-follower ✓ Inverting amplifier ✓ Phase shift ✓ Gain-bandwidth product  After completing this section, you should be able to 1-2 OP-AMP Discuss op-amp modes and Input Modes several parameters Identify the schematic and symbol and IC package terminals Parameters Describe the input signal modes Explain the differential mode Explain the common mode 1-2 OP-AMP Input Modes and Parameters After completing this section, you should be able to Define and discuss op-amp parameters Define common-mode rejection ratio (CMRR) Calculate the CMRR Express the CMRR in decibels Define open-loop voltage gain Explain maximum output voltage swing Explain input offset voltage Explain input bias current Explain input impedance Explain input offset current Explain output impedance Explain slew rate Explain frequency response Compare op-amp parameters for several devices OP-AMP Input Modes and Parameters OP-AMP Input Modes and Parameters OP-AMP Input Modes and Parameters OP-AMP Input Modes and Parameters Common Mode Common Mode Rejection Ratio Input Offset Voltage Input Bias Current Input Offset Current Input Offset Current Slew Rate The slew rate is a measure of how quickly the output of an electronic device (like an operational amplifier or a comparator) can change in response to a rapid input signal. It represents the maximum rate of change of the output voltage per unit of time and is typically expressed in volts per microsecond (V/µs). Slew Rate Slew Rate Example: If an amplifier has a slew rate of 1 V/µs, it means the output voltage can change by 1 volt in 1 microsecond. Slew Rate High Slew Rate: A high slew rate allows the circuit to respond quickly to rapidly changing input signals, making it important in high-frequency applications like video processing or high-speed communications. Low Slew Rate: A low slew rate can cause distortion in the output signal, especially when amplifying high-frequency signals, as the output cannot keep up with the fast changes in the input. Slew Rate Why Use Negative Feedback? Why Use Negative Feedback? Why Use Negative Feedback? Table 1 Comparison of Op-Amp Parameters Voltage-Follower The voltage-follower configuration is a special case of the noninverting amplifier where all of the output voltage is fed back to the inverting input by a straight connection, as shown in Figure 1–19. Voltage-Follower As you can see, the straight feedback connection has a voltage gain of 1 (which means there is no gain). The closed-loop voltage gain of a noninverting amplifier is as previously derived. Since B = 1 for a voltage-follower, the closed-loop voltage gain of the voltage- follower is Voltage-Follower The most important features of the voltage-follower configuration are its very high input impedance and its very low output impedance. These features make it a nearly ideal buffer amplifier for interfacing high-impedance sources and low-impedance loads.