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sinara-hw / Sayma_RTM

RTM board with 8-channel GS/s DAC, 125MS/s ADC and flexible clock circuit
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N12V0A/P12V0A diodes? #69

Closed hartytp closed 5 years ago

hartytp commented 5 years ago

@gkasprow I think the answer to this is "no" but to double check....

Do we need diodes on the P12V0/N12V0 lines to ensure that they start up correctly (i.e. to avoid the usual issues where one rail turns on too fast and reverse-biases the other one via OpAmp protection diodes etc)? Currently there are no such diodes on BaseMod, but with all channels populated there could be quite a lot of reverse current.

gkasprow commented 5 years ago

This issue was observed at the output of the LDOs. I already implemented them. obraz

gkasprow commented 5 years ago

I implemented them on BaseMod. Sayma RTM has increased startup time of the -6V converter so it will start later than +6V

hartytp commented 5 years ago

What about the p and n 12v?

gkasprow commented 5 years ago

we did not observe such issue with these rails. I can increase the startup time of -12V converter.

hartytp commented 5 years ago

Ok. Ime these kinds of issues are quite dependent on what kind of load is present. Personally I’d stick the diodes there to be safe.

gkasprow commented 5 years ago

do you mean diodes at the DC/DC converter output? such diodes are already part of the buck converters.

hartytp commented 5 years ago

yes, sorry, you're right. This is an issue for LDOs, not bucks.