On Fri, 21 Oct 2016 10:59:59 +0200, you wrote: >On Fri, 21 Oct 2016 00:20:43 -0400 >Scott Stobbe <scott.j.sto...@gmail.com> wrote: > >> The bad side of a 7912 is in long-term stability and tempCo, the sample I >> tested had at least a 150 ppm/degC tempCo, which is going to put a serious >> lump/bump in the 10s tau to gps crossover point on an allan deviation plot. > >If the Thunderbolt ist most sensitive to the -12V input, why not use >something like the LT3090? Its temperature coefficient is quite low >in the order of a few ppm/°C around room temperature. Using a metal >film resistor that should keep the output variations low as well. >As added bonus, you get a very low output noise. > >And while you are at it, use three LT3090 for the positive supplies :-) > > Attila Kinali
Or if space is not an issue, use a discrete reference or zener, operational amplifier, and pass transistor for better performance yet at less cost. If all of the supplies are to be regulated, then use a common reference to further save cost. Separating the reference, error amplifier, and feedback network from the power pass transistor lowers the effects from thermal feedback. _______________________________________________ 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.