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Page 1: sample ques vlsi

1) Design a CMOS inverter circuit of following parameters: VT0n= 0.6V, µnCox= 60µA/V2, (W/L)n= 8,

VT0p = -0.7V, µpCox = 25µA/V2, (W/L)p=12.Supply voltage = 3.3 volt. Channel length of both

transistor is 0.8µm. Determine (Wn/Wp) ratio so that switching threshold voltage of inverter circuit

Vth=1.4 volt.

2) A company has access to a CMOS fabrication process with the following device parameters listed

below:

µnCox=120 µA/V2, µpCox=60 µA/V

2, L=0.6µm for both NMOS and PMOS, VT0n=0.8V, VT0p= -1.0V,

Combined load capacitance value= 300fF and Wmin= 1.2µm.Design a CMOS inverter by determining

channel width Wn and Wp of NMOS and PMOS transistors such that propagation delay times tPHL ≤

0.2ns and tPLH ≤ 0.15ns.

3) Find the region of operation for the transistor M4 and M5 in the given configuration. All the

transistors have identical sizes. Assume VDD = 2.5 V, and VTn = 0.4 V, W = 1μm, L = 0.25 μm,

kn’ = 115 μA/V2.