[time-nuts] Linear voltage regulator hints...

[Richard (Rick) Karlquist]

Hittite introduced a "low noise" reference a
few years ago, but it was only low noise when
filtered with a big cap.  IOW, the cap did
all the heavy lifting and the IC was nothing
special.  Good marketing, bad engineering.

Rick

On 12/9/2014 4:30 AM, Bob Camp wrote:
> Hi
>
>> On Dec 8, 2014, at 10:35 PM, Brooke Clarke <brooke at pacific.net> wrote:
>>
>> Hi Rich:
>>
>> Did you use the 723 or . . . .?
>> As far as I know the 723 is supposed to have low noise.
>
> There are more modern parts with lower close in noise. Linear Technology has a number of them. Your filter caps take out the broadband stuff, close in is all that really matters.
>
> Bob
>
>>
>> Mail_Attachment --
>> Have Fun,
>>
>> Brooke Clarke
>> http://www.PRC68.com
>> http://www.end2partygovernment.com/2012Issues.html
>> http://www.prc68.com/I/DietNutrition.html
>> Richard (Rick) Karlquist wrote:
>>>
>>>
>>> On 12/8/2014 4:53 PM, Bert Kehren via time-nuts wrote:
>>>> We solved that problem by attaching the regulators to the FRK back plate
>>>> which is with fan control is kept within 0.01C. We did not do it for that
>>>> purpose but found that we needed some more heat in order to keep the fan in an
>>>>   optimum fan speed. Rb, OCXO and Fan power transistor are on the back
>>>> plate.  Works for us.
>>>> Bert Kehren
>>>>
>>>
>>> When I designed the E1938A, I chose a reasonable looking voltage
>>> reference IC and put it inside the oven.  I figured that was
>>> the end of it as far as tempco was concerned.  It was, but it
>>> turned out that the *noise* of the reference was unacceptable
>>> and of course the oven does nothing to fix that.  I had to
>>> switch to a lower noise reference.
>>>
>>> Rick Karlquist N6RK
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>