Consider the NMOS cascode current source in Figure 10.18. The circuit parameters are \(V^{+}=5 \mathrm{~V}, V^{-}=-5 \mathrm{~V}\), and \(I_{\mathrm{REF}}=100 \mu \mathrm{A}\). All transistors are matched with parameters \(V_{T N}=0.5 \mathrm{~V}, K_{n}=100 \mu \mathrm{A} / \mathrm{V}^{2}\), and \(\lambda=0.02 \mathrm{~V}^{-1}\).

(a) Determine \(I_{O}\) for \(V_{D 4}=-2 \mathrm{~V}\).

(b) Determine the percent change in \(I_{O}\) as \(V_{D 4}\) changes from -2 to \(+2 \mathrm{~V}\).

IREF V+ M4 M3 M M2 VDA Figure 10.18 MOSFET cascode current mirror