For a single-pole op-amp with open-loop DC gain A_OL and unity-gain bandwidth f_T, the gain-bandwidth product equals which?
AA_OL + f_3dB always sum form
BA_OL · f_3dB = f_T (single-pole)
CA_OL / f_3dB only ratio form
DA_OL² · f_3dB only squared form
Answer & Solution
Correct answer: B. A_OL · f_3dB = f_T (single-pole)
Single-pole rolloff: |A(f)| = A_OL/√(1+(f/f_3dB)²). Above f_3dB: |A|·f ≈ A_OL·f_3dB = f_T. Sets achievable bandwidth at any closed-loop gain.
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