[time-nuts] Anybody want a Thunderbolt power supply

Gerhard Hoffmann dk4xp at arcor.de
Mon Sep 5 20:33:18 EDT 2016

Am 01.09.2016 um 06:56 schrieb Gerhard Hoffmann:
> Am 01.09.2016 um 05:35 schrieb Charles Steinmetz:
>> The suggestion to use LT3042s is a good one, but note that it has an 
>> output current rating of 200mA.  The Tbolt needs ~250mA at +5v, and 
>> ~700mA at +12v [at startup -- but only ~150mA steady-state, depending 
>> on ambient temperature].  LT3042s can be used in parallel, so two of 
>> them for the +5v supply and four of them for the +12v supply would be 
>> required.  That isn't so bad for the +5v supply, but seems excessive 
>> for the +12v supply (particularly when three of the four are needed 
>> only during warmup from cold).
> I have made a stamp-sized layout for LT3042 + external npn power 
> transistor
> as shown in the data sheet.
> Not fabricated, let alone tested.

fabricated on a rainy Sunday and initially tested.
Output voltage is 5 Volts.


The preliminary noise spectrum is


without appropriate shielding, powered from R&S NGT20 @ 8V.
The faster than 1/f noise rise is caused by the pre-amplifier.

Still quite OK.

regards, Gerhard

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