It is hard to ignore that there is a consistent grouping of the PSoC 3 and PSoC 5 architectures. I do not recall ever seeing a document title with 3/4, 4/5 or 3/4/5 referenced together. I see that also in references to applicability to solutions. Are 3/5 more suited to analog? What does separate PSoC 4 ? I would like to understand it.
What about PSoC 6. What bucket does it fall in ? A new bucket ?
I will appreciate if someone can enlighten me
PSoC3 and PSoC 5 share the same resources, (nearly) no difference between them but the PSoC3 has got an old-fashioned 8055 CPU core, while the PSoC5 has got a more modern ARM M3 core.
PSoC4 has got some different resources and a much cheaper ARM M0 core. Some family members have got BLE
PSoC6 is unique; there will be two cores, both ARM, but different ones.
So as long as you are staying to low volume productions / prototypes and do not need BLE, the PSoC5 can be your choice.