An n-channel MOSFET has the following parameters: μn = 400 cm2 /V−s tox = 500Å L = 2 μm W = 20 μm VT = +0.75 V Assume the transistor is biased in the saturation region at VGS = 4 V. (a) Calculate the ideal cutoff frequency. (b) Assume that the gate oxide overlaps both the source and drain contacts by 0.75 μm. If a load resistance of RL = 10 kΩ is connected to the output, calculate the cutoff frequency.
Given VDD = 3 V and using IREF = 100 μA, it is required to design the following circuit to obtain an output current whose nominal value is 100 μA. Find R if M1 and M2 are matched and have channel lengths of 1 μm, channel widths of 10 μm, Vt = 0.7 V, and kn′ = 200 μA/V2. What is the lowest possible value of Vo ? Assuming that for this process technology the Early voltage VA′ = 1 /λ′ = 20 V/μm, find the output resistance of the current source. Also, find the change in output current resulting from a +1 V change in V0. Solution aprox. : VGS = 1.016 VR = 19.84 kΩ, Vo, min = 0.316 V, Ro = 0.2 MΩ, ΔIo = 5 μA Solution acc. : VGS = 1.00854 V, R = 19.914 kΩ, Vo, min = 0.30854 V, Ro = 0.2 MΩ, ΔIo = 5 μA