课程名称︰电子学(二)
课程性质︰电机工程学系大二下必修
课程教师︰林宗贤
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）︰2020/3/31
考试时限（分钟）：50分钟
试题 :
1.(10%) Please briefly describe two advantages of differential amplifiers.
2.(40%) A current-mirror-loaded NMOS differential amplifier in Fig.1 operates
with a bias current I of 200μA. The NMOS transistors are operated at
Vov = 0.2V and the PMOS devices at abs(Vov = 0.3V). The early voltages
are 20V for the NMOS and 12V for the PMOS transistors. Please find Gm,
Ro, and Ad.
VDD
↑
∣
┌──┴──┐
└→ ←┘
∥──∥
┌─ ∣ ─┐
├──┘ ∣
│ ├ Vο
─┘ └─
vg1─∥ ∥─vg2
└→ ←┘
│ │
└──┬──┘
⊕↓I
│
-VSS
Fig.1
3.(50%) The amplifier in Fig.2 is biased to operate at gm = 5mA/V, and has the
following component values : Rsig = 100kΩ, RG1 = 47MΩ, RG2 = 10MΩ,
Cc1 = 0.01μF, RS = 2kΩ, CS = 10μF, RD = 4.7kΩ, RL = 10kΩ, and
Cc2 = 1μF. Please find Am, fp1, fp2, fp3 and fL.
VDD
↑ ↑
│ │
│ RD Cc2
RG1 ├─∥──┐ +
Cc1 │ ─┘ │
┌─Rsig──∥─┼─∥ RL
+ │ │ ─→ │
Vsig⊕ RG2 ├─┐ │ Vο
- │ │ RS ＝CS │
│ │ │ │ │
≡ ≡ ≡ ≡ ≡ -
Fig.2