Description
Note:
(1) Please use A4 size papers.
(2) Please use the SPICE model on page 3 for simulation and calculation.
1. [MOSFET DC Biasing, 60%] Use the drain current equations below. Don’t consider channel-length modulation and body effect. Assuming Wdrawn /Ldrawn =20μm/2μm,sketchIX ofM1 asafunctionofVX increasing from 0 V to VDD = 5 V. (Note: finish this part before the midterm exam)
𝐈 𝐈 𝐈 𝐈
= μ 𝐂 𝐖 [(𝐕 − 𝐕 )𝐕 − 𝟏 𝐕 𝟐] (NMOS in triode region) 𝐃 𝐧𝐨𝐱𝐋𝐞𝐟𝐟 𝐆𝐒𝐓𝐇𝐃𝐒𝟐𝐃𝐒
= 𝟏 μ 𝐂 𝐖 (𝐕 − 𝐕 )𝟐 (NMOS in saturation region) 𝐃 𝟐𝐧𝐨𝐱𝐋𝐞𝐟𝐟 𝐆𝐒 𝐓𝐇
= μ 𝐂 𝐖 [(𝐕 − |𝐕 |)𝐕 − 𝟏 𝐕 𝟐] (PMOS in triode region) 𝐃 𝐩𝐨𝐱𝐋𝐞𝐟𝐟 𝐒𝐆 𝐓𝐇 𝐒𝐃𝟐𝐒𝐃
= 𝟏 μ 𝐂 𝐖 (𝐕 − |𝐕 |)𝟐 (PMOS in saturation region) 𝐃 𝟐𝐩𝐨𝐱𝐋𝐞𝐟𝐟 𝐒𝐆 𝐓𝐇
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2. [MOSFET Small-Signal Model] Assume Wdrawn / Ldrawn = 20 μm / 2 μm. (a) [20%] Use Pspice to plot the drain current of a NMOS as a function ofVDS increasingfrom0Vto5V,atVGS =1V,1.5Vand2V.Label the off, triode and saturation regions for each curve. Derive ro from each curve in the saturation region and compare it with hand-calculation result. (b) [20%] Use Pspice to plot the drain current of a NMOS as a function ofVGS increasingfrom0Vto3V,atVDS =5V.Derivegmfromthe curve when VGS = 2 V and compare it with hand-calculation result.
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Vacuum permittivity (𝛜𝐨) = 𝟖. 𝟖𝟓 × 𝟏𝟎−𝟏𝟐 (F / m) Silicon oxide dielectric constant (𝛜𝐫) = 𝟑. 𝟗
