Why circuit people don’t design layout also in the VLSI domain?

I’ve asked the same thing when I started in VLSI — like, why can’t one person do both circuit and layout design?

From what I’ve seen, it mostly comes down to specialization. I work more on the circuit side, and honestly, it takes a lot of time to optimize transistor sizing, meet performance targets, and run simulations. The layout side is a whole different world — you have to follow design rules, worry about parasitics, do DRC/LVS… it's very detailed.

So, usually in the industry, you have separate layout engineers who are experts in that area. It makes the whole process faster and more efficient.

Hi! Good question — in the VLSI domain, circuit designers and layout designers usually handle separate tasks because the workflows and tools are quite different.

As someone who's worked in analog circuit design, I can tell you — we focus on functionality, performance specs (gain, bandwidth, power, etc.), and we spend a lot of time running simulations, tweaking parameters, and making sure the design meets the requirements.

Meanwhile, layout design is more physical. You're dealing with layers, spacing rules, parasitic extraction, DRC/LVS cleanups, and other physical constraints. That’s a different skillset altogether.

Sometimes, we do assist layout engineers or review the layout, especially when performance is sensitive (like in analog blocks), but doing both full-time? It’s just not practical in most companies.

Hey! That’s a pretty common question — and it’s a good one.

Basically, in VLSI, we split the work to keep things efficient. You’ll notice that circuit designers and layout engineers are kind of like two sides of the same coin. One focuses on logic, performance, and behavior, while the other handles the physical layout, routing, and silicon-level implementation.

You can imagine how time-consuming both parts are. If you had to do circuit design and layout for a whole block, you'd be buried in work!

We sometimes collaborate closely — for example, if there’s a critical analog design, the circuit person might guide layout placement to reduce mismatch or parasitics. But yeah, in general, we specialize to move faster and get better results.

Anyone here tried doing both roles in a startup or academic project? Curious how that experience was!