All transistors in the current-source circuit shown in Figure 3.49 (b) in the text have parameters \(V_{T P}=-0.4 \mathrm{~V}, k_{p}^{\prime}=50 \mu \mathrm{A} / \mathrm{V}^{2}\), and \(\lambda=0\). The bias sources are \(V^{+}=5 \mathrm{~V}\) and \(V^{-}=-5 \mathrm{~V}\). The currents are to be \(I_{Q 2}=200 \mu \mathrm{A}\) and \(I_{\text {REF2 }}=125 \mu \mathrm{A}\). For \(M_{B}\), we require \(V_{S D B}(\mathrm{sat})=0.8 \mathrm{~V}\), and for \(M_{A}\), we require \(V_{S D A}=4 \mathrm{~V}\). Transistors \(M_{A}\) and \(M_{B}\) are matched.

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

(b) Find the value of \(R_{D}\).

Figure 3.49(a):-

Transcribed Image Text:

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