Slide 1'&$%ECE/CE 3720: Embedded System DesignChris J. MyersLecture 19: Operational AmplifiersSlide 2'&$%Introduction to Analog Interfacing• Most embedded systems include components thatmeasure and/or control real-world parameters.• These include position, speed, temperature, etc.• Usually exist in a continuous, or analog, form.• Often need to amplify, filter, and convert these signals todigital form.• This chapter develops analog circuit building blocks fordata acquisition and control systems.1Slide 3'&$%Resistors(See Table 11.1)Slide 4'&$%Capacitors(See Table 11.2)2Slide 5'&$%DC Supply Filters and Bypass Capacitors(See Figures 11.1 and 11.2)Slide 6'&$%Transistor Models(See Figures 11.3, 11.4, and 11.5)3Slide 7'&$%Ideal Op Amps(See Figure 11.6)1. Voltage ranges are bounded by the supply voltages.2. Input currents are zero.3. Negative feedback drives Vxto equal Vy.4. Positive feedback or no feedback drives Voutto equal −Vsor +Vs.Slide 8'&$%Input Impedance(See Figures 11.7 and 11.8, and Table 11.4)4Slide 9'&$%Output Impedance(See Figure 11.9)Slide 10'&$%Offset Voltage and Current(See Figure 11.10 and Table 11.5)5Slide 11'&$%Eliminating Offset Voltage and Current(See Figure 11.11)Slide 12'&$%Bias Current(See Figures 11.12 and 11.13, and Table 11.6)6Slide 13'&$%Noise Voltage and Current(See Figure 11.14 and Table 11.7)Slide 14'&$%Frequency Response(See Figures 11.15 and 11.16, and Table 11.8)7Slide 15'&$%Affect of Load on Frequency Response(See Figure 11.17)Slide 16'&$%Step Response(See Figure 11.18)8Slide 17'&$%Types of Op Amps(See Table 11.9)Slide 18'&$%Saturation Properties(See Figures 11.19 and 11.20)9Slide 19'&$%A Voltage Comparator(See Figure 11.21)Slide 20'&$%Simple Rules for Linear Op Amp Circuits• Choose quality components.• Negative feedback required to create linear mode circuit.(See Figure 11.22)• Assume no current flows into the op amp inputs• Assume negative feedback equalizes input voltages.• Choose resistor values in the 1kΩ to 1MΩ range.• BW depends on the gain and the op amp performance.10Slide 21'&$%Simple Rules for Linear Op Amp Circuits (cont)• Equalize the effective resistance to ground at the two opamp input terminals.• Input impedance is input voltage / input current.(See Figures 11.23 and 11.24)Slide 22'&$%Simple Rules for Linear Op Amp Circuits (cont)• Match input impedances to improve common-moderejection ratio (CMRR).(See Figures 11.25 and 11.26)11Slide 23'&$%Inverting Amplifier(See Figures 11.27 and 11.28)Slide 24'&$%Determining Short-Circuit Current(See Figure 11.29)12Slide 25'&$%Noninverting Amplifier(See Figures 11.30 and 11.31)Slide 26'&$%Determining Short-Circuit Current(See Figure 11.32)13Slide 27'&$%Buffer Amplifier or Voltage Follower(See Figures 11.33 and 11.34)Slide 28'&$%Inverting Adder Amplifier(See Figure 11.35)14Slide 29'&$%Differential Analog Amplifier(See Figure 11.36)Slide 30'&$%Instrumentation Amplifier(See Figures 11.37 and 11.38)15Slide 31'&$%Multiple-Stage Amplifier(See Figure 11.39)fT=vuut11f12+1f22+ · · · +1fN2Slide 32'&$%Offset Adding Op Amp Circuit(See Figures 11.40 and 11.41)16Slide 33'&$%High-Gain Op Amp Circuit(See Figures 11.42 and 11.43)Slide 34'&$%Current-to-Voltage Circuit(See Figure 11.44)17Slide 35'&$%Voltage-to-Current Circuit(See Figure 11.45)Slide 36'&$%Integrator Circuit(See Figure 11.46)18Slide 37'&$%Derivative Circuit(See Figure 11.47)Slide 38'&$%Voltage Comparators with Hysteresis(See Figures 11.48 and 11.49)19Slide 39'&$%Voltage Comparators with Hysteresis (cont)(See Figures 11.50 and
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