**8.47 Consider the circuit shown in Fig. 8.16(a), using a 3.3-V supply and transistors for which Vt = 0.8 V and L = 1 μm. For Q1, kn = 100 μA/V2, VA = 100 V, and W = 20 μm. For Q2 and Q3, kp = 50 μA/V2 and VA = 50 V. For Q2, W = 40 μm. For Q3, W = 10 μm. (a) If Q1 is to be biased at 100 μA, find IREF. For simplicity, ignore the effect of VA.