[time-nuts] FE5682A inside pics

Ed Palmer ed_palmer at sasktel.net
Mon Dec 31 16:49:35 UTC 2012

Hi Fabio,

A few years ago I got one of the programmable FE5680 units.  It included 
the same small, square board that I can see in your pictures.  Only 3 
wires:  red, black, and orange.  My unit didn't have any EFC control.  
On a hunch, I checked the orange wire and found that it was the EFC 
lead.  By disconnecting it and injecting a DC voltage into the main 
board, I could adjust the frequency of the oscillator over a range of 
about +- 1.5 e-9 (i.e. 1.5 ns on the 1 PPS output) for a 0 - 5 volt input.


On 12/31/2012 9:45 AM, Fabio Eboli wrote:
> Positive update, in the broken unit
> the pin 10 goes to power module input,
> while the pin 8 goes to power module
> ground, and there is grounded.
> I powered the good unit and
> it locked in few minutes, wothout driving
> the EFC, the frequency seem very near
> the FE5680 I set against the GPS.
> The output 10MHz phase is influenced badly
> by input voltage up to 18V, and is
> stable after that, so the unit seem
> to be a 19-32V one.
> Now that the failed unit is still opened,
> I will try to check the inner working
> voltageon this, if anibody has any question
> or curiosity about the units, I still have it
> opened up...
> Fabio.

More information about the time-nuts mailing list