Problem: In a MOS cascade amplifier, the cascade transistor is required to raise the output resistance by a factor of 40. If the transistor is operated at VOV = 0.2 V, what must its VA be? If the process technology specifies V'A = 5 V/μm, what channel length must the transistor have? Given: VOV = 0.2 V, VA = ? V'A = 5 V/μm, L = ? Known: ro = VA/IDS = (V'A*L)/(IDS) ==> L = (ro*IDS)/(V'A) ==> V'A = IDS*ro gm = (2*IDS)/(VOV) where IDS = (1/2)*μn*Cox*(W/L)*VOV2 My Approach: From the known equations, I have derived the equations needed to obtain VA and L. The unknown variables needed are: IDS, then gm, then ro, which all then give me the values for VA and L with the derived equations. However, I just realized that in order to obtain IDS with the equation above, I would need μn*Cox*(W/L), which in this case seems unobtainable. Could someone please help me? I'm doing something wrong but I just can't seem to figure it out. Any help is GREATLY appreciated!