Chapter 10, Problem 10.35P

The modified Widlar current-source circuit shown in Figure P10.34 isbiased at $V^{+}=3V$ and $V^{-}=-3V$ . (a) For $I_{S1}=I_{S2}={10}^{-15}A$ and $R_{E1}=500\Omega$ , design the circuit such that $I_{REF}=0.5mA$ and $I_O=0.2mA$ .Neglect base currents. What are the values of $V_{BE1}$ and $V_{BE2}$ ? (b) Repeatpart (a) for $I_{S1}={10}^{-15}A$ and $I_{S2}=2\times {10}^{-15}A$ .