All transistors in the current-source circuit shown in Figure 3.49 (a) in the text have parameters \(V_{T N}=0.4 \mathrm{~V}, k_{n}^{\prime}=120 \mu \mathrm{A} / \mathrm{V}^{2}\), and \(\lambda=0\). Transistors \(M_{1}\) and \(M_{2}\) are matched. The bias sources are \(V^{+}=2.5 \mathrm{~V}\) and \(V^{-}=-2.5 \mathrm{~V}\). The currents are to be \(I_{Q 1}=125 \mu \mathrm{A}\) and \(I_{\mathrm{REF} 1}=225 \mu \mathrm{A}\). For \(M_{2}\), we require \(V_{D S 2}(\mathrm{sat})=0.5 \mathrm{~V}\), and for \(M_{1}\) we require \(V_{D S 1}=2 \mathrm{~V}\).

(a) Find the \(W / L\) ratios of the transistors.

(b) Find \(R_{D}\).

Figure 3.49(a):-

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IREFI V+ VGSI www RD=8kQ M VDSI M3 + VGS3 + VGS2 M2 (a)