I'm having an issue with slow (occasionally never) start-up of TPS65381.
While on other boards we have used this part we see the 3V3 rail come up within hundreds of milliseconds, on our new board it takes at least 3 seconds, sometimes as long as a couple of minutes, and rarely it will just not come up at all.
Here's what VDD6 (Ch2) and SDN6 (Ch1) look like during the stuck phase. As you can see there is a 6 msec periodic rampup of VDD6:
And here's a zoomed-in scope shot of the moment of SDN6 pulse:
I get the following register readings out of the SPI bus, taken during the Stuck bootup phase and again once the VDDx rails finally come up:
Any ideas on what's causing this? The precise 6msec period of that first scope shot seems significant but I don't note any reference to that in the datasheet.
Thanks very much,
Connor
