XK-1 power supply sequencing puzzle

[leon_heller]

Does anyone know why the XK-1 power supply doesn't use a chip to ensure that the core supply isn't applied until the 3.3V supply is stable? Perhaps the linear regulator used always brings the 3.3V supply up quicker than the 1.0V switcher. Interestingly, the XS1-L1 reference design does have a sequencer chip, although that also uses a linear 3.3V regulator.

[Folknology]

It's a perfect example of how not to design the Xmos power sequencing ;-)
No supply sequencing & no power monitoring with RST_n/TRST_n

[bearcat]

The issue of power supply sequencing and JTAG reset's came out not long ago. It appears as XMOS redesigns the boards, they add the design criteria. I would review the latest reference designs to decide what is recommended.