Using vdd = 1.8 v and a pair of matched mosfets, design the current-source circuit of fig. 8.1 to provide an output current of 150-μanominal value. to simplify matters, assume that the nominal value of the output current is obtained at vo vgs. it is further required that the circuit operate for vo in the range of 0.3 v to vdd and that the change in io over this range be limited to 10% of the nominal value of io. find the required value of r and the device dimensions. for the fabrication-process technology utilized, μncox = 400 μa/v2, v a = 10 v/μm, and vt = 0.5 v.