[time-nuts] Anybody want a Thunderbolt power supply?
davidwhess at gmail.com
Fri Oct 21 12:21:38 EDT 2016
On Fri, 21 Oct 2016 10:59:59 +0200, you wrote:
>On Fri, 21 Oct 2016 00:20:43 -0400
>Scott Stobbe <scott.j.stobbe at 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.
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