EE 140 ANALOG INTEGRATED CIRCUITS SPRING 2011 C. Nguyen PROBLEM SET #12 Issued: Tuesday, April 26h, 2011 Due: Tuesday, May 3rd, 2011, 5:00 p.m. in the EE 140 homework box in 240 Cory 1. The ac schematic of a shunt-shunt feedback amplifier is shown in Fig. PS12.1. (“ac schematic” means that biasing is not shown, but that you should assume that all devices are biased appropriately.) All transistors have ID = 1 mA, W/L = 100, k’ = 60 A/V2, and = 1/(50 V). a. Calculate the overall gain vo/ii, the loop transmission, the input impedance, and the output impedance at low frequencies. b. If the circuit is fed from a source resistance of 1 k in parallel with ii, what is the new output resistance of the circuit? 5 kM15 k 5 k10 kM2M3iivo Fig. PS12.1 2. Assume the BiCMOS amplifier of Fig. PS12.2 is fed from a current source. Calculate the low-frequency small-signal transresistance vo/ii, the loop gain, and the input and output impedances of the circuit. Use the following parameters in your calculation: IS = 10-16A, F = 100, rb = 0, VA ∞, nCox = 200 A/V2, Vt = 0.6V, and = 0.EE 140 ANALOG INTEGRATED CIRCUITS SPRING 2011 C. Nguyen Fig. PS12.2 3. A CMOS feedback amplifier is shown in Fig. PS12.3. If the dc input voltage is zero, calculate the overall voltage gain vo/vi and the output resistance. Compare your answer with a SPICE simulation. Use the following: μnCox = 60 A/V2, μpCox = 30 A/V2, Vtn = 0.8 V, Vtp = -0.8 V, λn=|λp| = 0.03 V-1, and γn = γp = 0. Fig.
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