In the LF155 BiFET op-amp in Figure 13.25, the combination of (Q_{3}, J_{6}), and (Q_{4}) establishes the

Question:

In the LF155 BiFET op-amp in Figure 13.25, the combination of $Q_{3}, J_{6}$, and $Q_{4}$ establishes the reference bias current. Assume the power supply voltages are $V^{+}=10 \mathrm{~V}$ and $V^{-}=-10 \mathrm{~V}$. The transistor parameters are $V_{E B}(\mathrm{on})=$ $0.6 \mathrm{~V}, V_{B E}(\mathrm{on})=0.6 \mathrm{~V}$, and $V_{P}=4 \mathrm{~V}$ for $Q_{3}, Q_{4}$, and $J_{6}$, respectively. Determine the required $I_{D S S}$ value for $J_{6}$ to establish a reference current of $I_{\mathrm{REF}}=0.8 \mathrm{~mA}$.

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