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Consider the amplifier of Fig. 10.74, where (W/L)1−4 = 50/0.5 and ISS = I1 = 0.5 mA. (a) Estimate the poles at nodes X and Y by multiplying the small-signal resistance and capacitance to ground. Assume that CX = CY = 0.5 pF. What is the phase margin for unity-gain feedback? (b) If CX = 0.5 pF, what is the maximum tolerable value of CY that yields a phase margin of 60∘ for unity-gain feedback? Figure 10.74

Consider the amplifier of Fig. 10.74, where (W/L)1−4 = 50/0.5 and ISS = I1 = 0.5 mA. (a) Estimate the poles at nodes X and Y by multiplying the small-signal resistance and capacitance to ground. Assume that CX = CY = 0.5 pF. What is the phase margin for unity-gain feedback? (b) If CX = 0.5 pF, what is the maximum tolerable value of CY that yields a phase margin of 60∘ for unity-gain feedback? Figure 10.74

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Consider the amplifier of Fig. 10.74, where ( W / L ) 1 − 4 = 50 / 0.5 and I S S = I 1 = 0.5 m A . (a) Estimate the poles at nodes X and Y by multiplying the small-signal resistance and capacitance to ground. Assume that C X = C Y = 0.5 p F . What is the phase margin for unity-gain feedback? (b) If C X = 0.5 p F , what is the maximum tolerable value of C Y that yields a phase margin of 60 ∘ for unity-gain feedback? Figure 10.74

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