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Ve311 Homework #5

Note:

(1) Please use A4 size papers.

(2) Please use the SPICE model on page 2 for simulation and calculation.

1. [Common-Source with Resistive Load]

(a) [40%] Assume λ = 0 and γ = 0. For VDD = 5 V, Vin = 0.9 V + small

signal, RD = 15 kΩ and Ldrawn = 2 µm, find out the value Wdrawn to obtain

a voltage gain |Aυ

| > 10 and VOUT (the DC biasing voltage at the output)

close to 2.5 V as much as possible.

(b) [30%] Using the DC biasing condition in (a), plot VOUT as a function

of VIN (from 0 V to 5 V) by DC sweep in Pspice. Compare the handcalculation result in (a) with the simulation result here. Note: the slope of

the VOUT versus VIN curve at VIN = 0.9 V is the Av

.

(c) [30%] Using the DC biasing conditions in (a), plot Vout as a function

of time (from 0 to 0.1 second) in Pspice, when Vin = 0.9 V + B ×

sin(2π100t) and B = 0.01 V, 0.1 V and 1 V. What do you observe when

the amplitude increases?

2

Vacuum permittivity (𝛜𝐨) = 𝟖. 𝟖𝟓 × 𝟏𝟎−𝟏𝟐 (F / m)

Silicon oxide dielectric constant (𝛜𝐫

) = 𝟑. 𝟗