ECE142_2007FALL_EXAM1__[0]

ECE142_2007FALL_EXAM1__[0] - the small signal output...

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ECE142A Fall 2007 1 ECE142A Mid-Term Examination Fall 2007 Wednesday November 7 th - Two Hours Attempt All Questions 1. Sketch the current-voltage characteristics for the transistors shown in Figure 1. Assume that the magnitude of the respective threshold voltages is about 1V. Use the attached sheet for your sketches. [16] Figure 1 2. Derive the small signal input and output impedances for the circuit reproduced in Figure 2. Assume that V A = ± [10] Figure 2 3. Sketch the voltage transfer characteristics (V out vs. V in ) for the circuits shown in figures 3 (a) and (b). Assume that a moderate impedance load is connected from the output to ground. Sweep the input voltage from V ss to V dd or V EE to V CC as appropriate. [20] Figure 3 + - + - + - + - + - + - (a) (h) (c) (d) (±) (f) (g) + - + - (² ) Q1 Q2 VCC VEE Vout Vin M2 M1 Vdd Vss Vout Vin (a) (b) Rout Rin Q1 Re R2 R1
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ECE142A Fall 2007 2 4. Write down the configurations for transistors M1 through M3 in the circuit reproduced in Figure 4. Draw the equivalent small signal model for the amplifier (you may ignore
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Unformatted text preview: the small signal output impedance of the transistors). From your small signal model, write down the nodal equations and thus derive an expression for the small signal voltage gain. [26] Figure 4 5. A BICMOS Darlington configuration is shown in Figure 5. The bias voltage on the gate of M1, V B , is adjusted to set the DC output voltage to 2V with V DD = 5V. Calculate the bias currents in both devices [10] and then calculate the small signal voltage gain for the circuit. Assume a value of 0.77V for V BE . You may ignore the body effect for the MOS transistor or include it for a bonus of 5 marks. The MOS transistor parameters are: e C ox = 60 A.V-2 , = 0.5V 1/2 , 2 | F | = 0.7, = 0, W/L = 40/1 and V T0 = 0.8V. For the bipolar transistor: I o = 10-16 A, = 100 and V A = . [18] Figure 5 TJC 11/2/07 R1 R2 R3 R4 R5 RL Vin + rs C1 M1 M3 M2 C2 Vout +-Vdd Vin + 1k M1 Q2 1k Vout B V V DD...
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This note was uploaded on 02/27/2012 for the course CHEMISTRY/ CH/ECE/PH/ taught by Professor Faculty during the Spring '08 term at Cooper Union.

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ECE142_2007FALL_EXAM1__[0] - the small signal output...

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