HP5385A OCXO Timebase

[Miti]

I attached the Gerber file, schematic and BOM. Some components in the BOM must be selected for your OCXO specs.

[wkb]

Having just acquired an OCXO-deprived HP5385A I stumbled onto this thread.
i happen to have 5 of these CTI OCXO's on hand so..

And, maybe useful, I have a sort-of datasheet for them.  See attached.

From that datasheet I conclude that the 4.095V reference is what is needed for Miti's PCB?

Wilko

[SoundTech-LG]

How does the CTI you mention stack up, compared to Oscilloquartz 8663XS ?

[wkb]

No idea, you would have to compare the specs of the Oscilloquartz against the CTI specs.

I plan to fit a CTI for those cases the Hp5385A needs to be used outside of my ham shack. While in the shack it will be fed a proper reference either from my Efratom Rb or a Samsung UCCM GPSDO

Wilko

[SoundTech-LG]

Right. Agree completely with your plan.

[Miti]

From that datasheet I conclude that the 4.095V reference is what is needed for Miti's PCB?

I can’t see how you concluded that based on the data sheet, but I may have missed something.
The idea is to have the tightest possible adjustment range around the VC that would give you a 10MHz output. You can’t know what that VC value is until you measure it. So power on your OCXO, let it stabilize for couple of weeks, then measure its frequency with your frequency counter using GPSDO as reference. Adjust the VC until you get 10MHz. See what that VC is and calculate the components to generate that voltage +/- few tens to a hundred mV so you can have fine adjustment, and that should be around 2V.

[wkb]

Well, the adjustment voltage range the datasheet gives brings me to that conclusion.

In industrial production they cannot run the OCXO for a couple of weeks to see what voltage reference might match best. So I assume they go for a ref that allows full range adjustments. One could use a coarse/fine pair of adjustments if need be?

Wilko

[PerArdua]

Thank you for sharing your design Miti.

Would you be able to confirm the dimensions between pins of the OSC5A2B02 please? I've not been able to find a datasheet with this information online.

[Miti]

Thank you for sharing your design Miti.

Would you be able to confirm the dimensions between pins of the OSC5A2B02 please? I've not been able to find a datasheet with this information online.

You can measure it in the Gerbers, my measurement shows 19.05mm between corner pins and pin 2 equal distance to 1 and 3.
I can't remember if I found the datasheet or I measured but I created the Eagle library. It seems to fit well.