What Analog IC Interviews Actually Test in 2026

If you've prepped from a few different analog interview question lists, you've probably noticed the same handful of "trick" questions keep resurfacing across companies: the source-degenerated LNA transconductance question, the current-mirror matching question, the two-stage amplifier compensation question. That's not a coincidence, and it's not laziness on the interviewer's part. Each of these questions is a compact test of a deeper skill, and understanding what's actually being measured will do more for your prep than memorizing more questions.

For the full breadth of topics, our top analog design interview questions and analog & mixed-signal interview guide are the place to drill. This post is about the pattern underneath them.

The LNA transconductance trick isn't about LNAs

A classic prompt: "You've matched an LNA with source degeneration and a series input inductor. What's the overall transconductance at resonance?" The trap is answering with a device-size-dependent formula, when at resonance the answer collapses to something independent of device sizing. Interviewers don't ask this because they need you to design an LNA on a whiteboard — they ask it because it reveals whether you actually derive circuits from first principles or you've pattern-matched a formula without understanding where it came from. A candidate who works through the resonance condition live, even slowly, reads as more capable than one who blurts a memorized answer without being able to explain why it's independent of size.

Current-mirror matching is a proxy for your layout instincts

"How do you improve matching between two current-mirror transistors?" has a known-good answer shape: raise overdrive voltage, keep the mirror ratio modest rather than pushing into the hundreds, add cascoding. But the real signal to the interviewer is whether you're thinking about the circuit as something that has to survive fabrication — mismatch, gradients, layout-dependent effects — rather than as an idealized schematic. This is the same instinct that shows up later in your career when a design works in simulation and fails in silicon. Interviewers are trying to hire that instinct early.

Two-stage compensation tests whether you understand feedback, not just poles

Being asked to explain why Miller compensation causes pole splitting is really a test of whether you understand feedback systems generally, not just this one compensation topology. Candidates who can only recite "Miller compensation splits the poles" without explaining the mechanism — how the compensation capacitor's Miller-multiplied effective capacitance moves the dominant pole down while pushing the non-dominant pole up — struggle when the interviewer perturbs the question slightly, for instance by asking what happens if the load capacitance changes, or how a right-half-plane zero from the same capacitor complicates things.

What this means for your prep

Don't optimize for question coverage alone. For every classic question you drill, spend time on the "why" behind the expected answer, and practice explaining that reasoning out loud — most interviewers care more about how you get to an answer than whether you land on it instantly. This is also exactly why timed, silent practice from a question bank underperforms live mock interviews: a mock interviewer will perturb your answer the way a real one will, and you'll find out quickly whether your understanding is load-bearing or just memorized.

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FAQ

Q: Should I still memorize standard derivations if interviews are really testing understanding? Yes — memorization and understanding aren't opposites here. Knowing the standard derivation cold frees up working memory to reason about the follow-up questions, which is where understanding actually gets tested.

Q: How do I know if I actually understand a concept versus just remember it? A good test: can you explain what happens if one parameter in the problem changes (higher frequency, different load, mismatched device sizes)? If you can only reproduce the original answer, you likely have a memorized result rather than a derived one.

Q: Do these patterns hold at both large companies and startups? Yes, though startups tend to skip further into applied follow-ups faster (e.g., "how would this behave on real silicon with this process's known mismatch") since they often need engineers to be productive with less onboarding runway. See our startup vs. big chip company hiring guide for more on that difference.

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Practicing these derivations out loud with someone who will actually push back on a shallow answer is the fastest way to find out where your understanding is thin. You can book a mock interview with a working analog IC engineer on MockVise and get direct feedback on whether your reasoning — not just your final answer — would hold up in a real loop.