3 ms·
In general, analog chips are easier to fab because less transistors are involved and thus minimum feature size isn't as important. Typical parts have merely a h
by blackguardx 9y ago
In general, analog chips are easier to fab because less transistors are involved and thus minimum feature size isn't as important. Typical parts have merely a handful of transistors.
Cutting-edge analog ICs are a different beast, though. Tightly controlled processes are the norm and post-fab trimming is common.
- vvanders 9y agoI've always heard that analog is harder because you need to characterize the full behavior of the transistor as opposed to just setup and hold times for digital. Then again I only tinker with discrete components so it's an area that's somewhat foreign to me.
- eternauta3k 9y agoYep. Then do that over temperature. Then model the statistical variations.
- blackguardx 9y agoIt all depends on what you are trying to do. Some good analog parts use a BiCMOS process with both BJTs and FETs, which is exotic and complicated. The margins of any process are usually complicated, though. Just look at how many billions it takes to develop a cutting edge digital process. In my opninion it would be easier to do interesting analog parts in a home lab than an interesting digital part. Making an opamp would be easier than a processor and more interesting than an XOR gate (around same # of transistors). Also, you can do some analog stuff with only NMOS or PMOS, which simplifies things by at least 50% compared to CMOS. For a home lab, you care about process and characterization, but variation isn't as much of a concern because you won't be making that many. Also, just look at the development of the semiconductor industry. Early factories (making analog parts) didn't look that much different from what you could cobble together in a garage. By the time they were doing integrated processors, things were a lot more high-tech.