课程名称︰电子学一
课程性质︰必修
课程教师︰吕良鸿
开课学院：电机资讯学院
开课系所︰电机工程学系
考试日期（年月日）︰103/12/26
考试时限（分钟）：50分钟
试题 :
Microelectronic Circuits I (Quiz 2)
date: 2014/12/26 (Fri)
time: 14:20~15:10
1. (50%) Figure shows an amplifier in which the load resistor R_D has been
replaced with another NMOS transistor Q2 connected as a two-terminal device.
Note that because V_DG of Q2 is zero, it will be operating in saturation at
all times, even when V_i = 0 and i_D2 = i_D1 = 0. Note also that the two
transistors conduct equal drain currents. Using i_D1 = i_D2, show that for
the range of v1 over which Q1 is operating in saturation, that is, for
V_t1 ≦ v_I ≦ v_O + V_t1
the output voltage will be given by
http://ppt.cc/1JsL
where we have assumed V_t1 = V_t2 = V_t. Thus the circuit functions as a
linear amplifier, even for large input signals. For (W/L)_1 = (5um/0.5um)
and (W/L)_2 = (5um/0.5um), find the voltage gain.
http://ppt.cc/k1k1
2. The bias circuit of figure is used in a design with V_G = 5V and R_S = 1kΩ.
For an enhancement MOSFET with k'_n(W/L) = 2mA/V^2 the source voltage was
measured and found to be 2 V. What must V_t be for this device? If a device
for which V_t is 0.5 V less is used, what does V_S become? What bias current
results?
http://ppt.cc/jlNZ