Sounds similar to the issues you encounter with Atmel and some other EEPROM/Flash based MCUs when they're not held in reset until VCC becomes stable.
http://atmel.force.com/support/articles/en_US/FAQ/Prevent-EEPROM-corruption Some more info: http://www.embedded.com/design/prototyping-and-development/4006422/Avoid-corruption-in-nonvolatile-memory On 8 June 2016 at 16:20, jimlux <jim...@earthlink.net> wrote: > On 6/8/16 6:19 AM, paul swed wrote: > >> The units were never intended for a slow ramp >> I assume it runs into a meta stable condition >> Neither on or off and then corruption >> Glad you're can repair them >> >> On Tuesday, June 7, 2016, Bob Camp <kb...@n1k.org> wrote: >> >> >>> > Interesting, we just had a similar issue on a circuit here at work.. > someone slowly brought the supply voltage up on a bunch of DC/DC > converters, and some didn't start. This was in initial checkout of a new > board. > > Switch it on with a bang, and it works just fine. > > So for some of these things there's apparently a minimum dv/dt. > > I've seen this before with DC/DC converters.. if the voltage drops too > low, they draw too much current - because they're basically constant power > devices- and the overcurrent trip shuts them down. There's a delicate > interplay between the overcurrent and undervoltage trips,both of which have > some sort of time constant, and I suspect that for a lot of circuits, the > "slow ramp up of input voltage" isn't something they are designed for. > Once it's up and running, when the supply sags, the UV trip works just > fine, tripping before the OC trip goes. > > > Linear regulators.. they may be not the most efficient thing in the world, > but they have a lot less "weird" behavior. (although I've had linear > regulators go into thermally driven oscillation) > > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Clint. *No trees were harmed in the sending of this mail. However, a large number of electrons were greatly inconvenienced.* _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.