“Willy Sanseny?” Elena asked, reading the name.

She learned from Chapter 7: “The flicker noise corner frequency for pMOS is three times lower than nMOS. Use pMOS for your input stage if you hate popcorn noise.”

Elena smiled. “Pull up a chair,” she said. “You’re not the first person to lose phase margin. Let me tell you about a professor from Leuven who wrote the best ‘cookbook’ in the world.”

In a cluttered lab at the twilight of the 2000s, Elena was staring at a dead circuit. Her first analog chip—a simple transimpedance amplifier for a photodiode—was oscillating like a frantic metronome. She had textbooks. Huge, heavy tomes on her shelf by Gray & Meyer, Razavi, and Allen & Holberg. But none of them answered the simple question screaming at her now: Where is my phase margin, and how do I fix it fast?