Solution Manual for Introduction to Mechatronic Design Do Not Circulate
Chapter 12 Real Operational Amplifiers and Comparators
12.1) Use the Internet to find the data sheet for the Microchip MCP6294 amplifier and use the specifications for
the device when it is operated with a single 5 V supply to answer the following questions.
a) For a circuit with a closed loop gain of 10 and desired maximum gain error of 10%, use the guidelines
provided in this chapter to determine the maximum signal frequency that can be amplified?
b) What would the actual gain be at that frequency?
c) How would these answers change if the power supply voltage were reduced to 3.3 V?
a) Only a typical GBW is specified at 10 MHz. To keep the gain error below 10% we need an open loop
12.2) Use the Internet to find the data sheet for the Microchip MCP6294 amplifier. If the MCP6294 amplifier
operates with a single 5 V supply across the full range of temperatures, what is the possible range of output
voltages for the circuit shown in Figure 12.10? You may neglect the effects of temperature on all other
circuit elements.
Figure 12.10 Circuit for Problem 12.2.
12.3) How much GBW is required of an op-amp in order for it to amplify a 10 kHz sine wave by a factor of 10
with a gain error of less than 1%?
12.4) Design a circuit to implement an inverting comparator with hysteresis having an approximately 200 mV
hysteresis band centered at approximately 1 V. Choose standard 5% resistors and report the expected
thresholds if the values of those resistors were exact.
12.5) What range of thresholds (min to max) would you expect to see in the circuit of Problem 12.4 if the 5%
resistors were at the outer limits of the tolerance?
12.6) For the circuit shown in Figure 12.11, what is Vout? Write an expression for Vout in terms of the relevant
device parameters.
Figure 12.11 Circuit for Problem 12.6.
12.7) In the circuit of Figure 12.11, what purpose does resistor R1 serve?
12.8) Using the Web, classify the following op-amps according to their input and output characteristics (i.e.,
RRI, RRO, RRIO): LM139A, MCP6031, OPA337, MC34072A, ADA4051-2, LT1012.
12.9) For the MC6294, across the range of temperatures from -40° to 125°C, what is the maximum expected
input offset voltage and input bias current? How do these numbers change if the temperature range is
reduced to -40° to 85°C?
12.10) For the circuit of Error! Reference source not found., what is Vout ? Write an expression for Vout in
terms of the relevant device parameters.
Figure 12.12 Circuit for Problem 12.10.
12.11) Locate a data sheet for a MAX9024 and answer the following questions:
a) How does its pin-out compare with that of the comparator shown in Figure 12.9?
b) How does its output stage compare with that described in Section 11.5?
c) How does its propagation delay compare with that of the specifications for the LM339A?