I have a question about power sequencing requested by FPGA/MCU datasheets. I always see in datasheets that a particular power supply input must reach a voltage level before another power supply input (for example Vcore before Vio). But every time I look at evaluation boards I can't find anything that does that (e.g. power sequencer ICs). My question is related to FPGAs and MCUs, and not to particular ICs that maybe must have a described power seq. to correctly work.
Since my evaluation boards never fault as power up, is this power sequencing really necessary? Or is it perhaps accomplished in some way by the decoupling capacitors?