Consider the noninverting opamp in Fig. 5.15 where , is a resistor with value , and is a resistor that varies over the range to . The opamp may be modeled as having infinite input impedance, , zero...

Consider the noninverting opamp in Fig. 5.15 where , is a resistor with value , and is a resistor that varies over the range to . The opamp may be modeled as having infinite input impedance, , zero output impedance, , and a voltage gain,

                            Av( ) s 104 1 s 104 ( ) + ⁄ 1 s 108 ( )

a. What is the worst-case (smallest) phase margin? What is the corresponding value of ?

b. What is the worst-case (lowest) bandwidth of the closed-loop amplifier? What is the corresponding value of ?

c. What is the worst-case (largest, slowest) time-constant of the closed-loop amplifier’s step response? What is the corresponding value of ?