D1.23 Consider a transconductance amplifier having the model shown in Table 1.1. If the amplifier load consists of a resistance RL in parallel with a capacitance CL, convince yourself that the voltage transfer function realized, Vo/Vi, is of the low-pass STC type. For example, this may be a suitable model when a transistor is driving an ultrasonic transducer. Consider the case where the transducer is a load with RL = 1 kΩ and CL = 4.5 nF, and find the largest value of Ro for which a 3-dB bandwidth of at least 40 kHz is provided. With this value of Ro, find the minimum value of Gm required to ensure a dc gain of at least 40 dB.
7.6 kΩ; 113 mA/V