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.
update:
fabricated on a rainy Sunday and initially tested.
Output voltage is 5 Volts.
<
https://www.flickr.com/photos/137684711@N07/29197476530/in/dateposted-public/
>
The preliminary noise spectrum is
<
https://www.flickr.com/photos/137684711@N07/29452163806/in/dateposted-public/>
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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