500K V C C 1 R 1. V OUT (t) M 1 -2V

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1 EE 330 Homework 8 Spring 2017 Due Friday March 3 Solve Problem 15 and any 8 of the remaining problems. Each problem is worth 10 points except Problem 15 which is worth 20 points. Unless stated to the contrary, assume all MOS transistors have model parameters μncox=100μa/v 2, VTn=1V, μn/μp =3, VTp=-1V and all BJT transistors have model parameters JSA= A, βn=100, and, βp=30. Problem 1 Assume the capacitors are very large. a) Determine the quiescent value of VC and VOUT b) Draw the small-signal equivalent circuit V DD =10V 500K 4K C V C 1 C Q 2 1 2K V(t) Problem 2 Determine the maximum value of R1 that will keep M1 in saturation. M1 has dimensions W=6u and L=2u and is in a process with ncox=100 A/v 2 pcox=30 A/v 2,VTNO=0.5V, VTPO= - 0.5V, COX=2fF/ 2, = 0, 4V R 1 (t) M 1 Problem 3 a) Determine the small-signal voltage gain of the circuit in the previous problem if the value of R1 is ½ the value needed to keep M1 in saturation b) Draw the small-signal equivalent circuit for the circuit in the previous problem. -2V Page 1

2 Problem 4 Consider the following circuit. a) Determine the total output voltage if VDD=5V, VSS=-2V, W1=10u, L1=2u, W2=3u and L2=1u. Assume the devices are from a process with parameters ncox=100 A/v 2 pcox=30 A/v 2,VTNO=0.5V, VTPO= - 0.5V, COX=2fF/ 2, = 0, b) Draw the small-signal equivalent circuit V DD M 2 M 1 V SS Problem 5 Assume the capacitors are all very large. a) Determine the quiescent value of VC and VOUT b) Draw the small-signal equivalent circuit V DD =32V 90K 3K V C C 1 C 2 Q 1 4K V(t)=V M sin(ωt+θ) 10K 1.5K C 3 Page 2

3 Problem 6 Obtain the quiescent output voltage 12V 12K (t) W=6μ L=4μ Problem 7 a) Determine the quiescent output voltage b) If the input is a 1KHz square wave with high and low values of 0V and 25mV, determine the output voltage -2V 20K W=6μ L=3μ (t) -2V 4V Page 3

4 Problem 8 Assume VIN is a low frequency sinusoidal waveform given by the expression VIN=.025sin1000t and assume that W=4μm, L=1μm for the MOSFET. The output voltage of this circuit should be a sinusoidal waveform of the same frequency as the input. Define the voltage gain to be the ratio of the p-p value of the output sinusoidal signal to the p-p value of the sinusoidal input signal. With this definition of gain, determine the voltage gain of this circuit if VXX=2V. V IN R FET RF V XX Problem 9 Consider the two circuits shown. a) Determine the output current for the bipolar circuit if AE1=300u 2 and AE2=1200u 2 and IIN=1mA.. Assume β is very large. b) Determine the output current for the MOS circuit if W1/L1=10 and W2/L2=20 and IIN=1mA. 8V 8V I IN I OUT I IN I OUT Q 1 Q 2 M 1 M 2 Problem 10 Express the output current for the bipolar circuit in terms of the input current and the emitter areas for the circuit of Problem 9. Assume β is very large. Also express the output current for the MOS circuit in terms of the input current and the W/L ratios for the circuit of Problem 9. What conclusion can be drawn about the relative performance between these two circuits?. Page 4

5 S 1 S 2 S 3 Problem 11 Three devices are shown. The color green is used to denote n-active and the red denotes polysilicon. Relative device dimensions are as indicated. Make a comparison of the performance of these structures. D 1 D 2 D 3 L/2 G L G 2 1 G 3 L L/2 W W W/2 W/2 Problem 12 Assume VXQ=2V. Determine the small-signal equivalent circuit of the one-port shown at the specified Q-point. 2 V I 4mA+ X 300 V X 1K V X Problem 13 The circuit shown has been proposed as a rectifier. Compare the dc performance of this circuit to that of the pn junction. Does is behave as a rectifier? Page 5

6 Problem 14 If R1=10K, size the device so that the amplifier has a quiescent output voltage of 3V. 4V R 1 (t) M 1-2V Problem 15 (Counts as 2 problems) Using ModelSim create a 4-bit Up/Down Counter. Include a select bit that allows it to switch modes, being an up-counter when the select is 0 and a down counter when the select is 1. Create a test bench for the code and show the following results/waveform. Page 6

7 Problem 15 (Counts as 2 problems) Using ModelSim create a 1-8 Demultiplexor (Demux). A Demux takes in one input and routes it to one of 8 outputs as determined by three selection bits. A symbol for a 1-8 Demux is shown below. Y 1 Y 2 F Input 1 8 Demux Y 3 Y 4 Y 5 Y 6 Outputs Y 7 Y 8 Select a b c Be sure to include your code and waveforms verifying the proper operation. Page 7

8 Problem 14 (extra credit) In the circuit shown the dimensions of the transistor are W=10u and L=1u. Assume C1 and C2 are very large. Determine the quiescent value of VD and VOUT V DD =5V R 3 =100K V D M 1 C 1 VIN(t)=VMsin(ωt+θ) R 1 =20K R 4 =50K R 2 =20K C 2 V SS =-2V Problem 12 (Counts as two problems) Using a hardware description language of your choice (Verilog, VHDL), design a serial to parallel converter. The converter should take in an 8 bit serial input and output an 8 bit parallel result, to be stored in a register file. Assume the serial input arrives prior to to each rising clock edge from a microcontroller using the same clock signal. Thus, a new bit of serial data is available on each clock pulse to be stored in the register file. In addition to the serial input and clock cycle, two other inputs should be available to the system as well. The first input is a reset, which when enabled will set the values in the register file to 0. The second input is a conversion enable, which when set high, the parallel register will be loaded with ones. When set low, the system resumes normal operation. When writing the test bench, assume the clock period is 10ns. Please submit the module code, test bench code, and simulation waveform to receive full credit. Page 8

I D1 I D2 V X D 1 D 2 EE 330. Homework Assignment 6 Spring 2017 (Due Friday Feb 17)

I D1 I D2 V X D 1 D 2 EE 330. Homework Assignment 6 Spring 2017 (Due Friday Feb 17) EE 330 Homework Assignment 6 Spring 2017 (Due Friday Feb 17) Unless specified to the contrary, assume all n-channel MOS transistors have model parameters μncox = 100μA/V 2 and VTn = 1V, all p-channel transistors