ISSCC '98 Analog Tutorial

Multistage opamp compensation root loci

f_T=10GHz A_V=10 C_IN=0.1pF C_L=10pF (Steep tapering)

• Poles initially coincident
• First stage output pole dominant
• With feedforward zero cancellation, poles initially coincident

• Poles initially coincident
• Second stage output pole initially dominant
• With feedforward zero cancellation, poles initially coincident

• Poles initially coincident
• Poles initially distributed
• With feedforward zero cancellation, poles initially distributed