[time-nuts] LTE Lite Came!!

SAIDJACK at aol.com SAIDJACK at aol.com
Mon Nov 17 18:39:48 EST 2014

Hi Jim,
thanks for your question. The reason we put that note in there is  two-fold:
1) On these 20MHz units the TCXO output in fact can drive 50 Ohms inputs as 
 we put a strong buffer on the board, but the synthesized RF output and the 
 1PPS output cannot drive 50 Ohms. Those two are CMOS 1M Ohms input  only.
Using 50 Ohms impedance on the TCXO output will however heavily tax  the 
internal power supply and CMOS buffer, and create heating on the board  right 
next to the TCXO which will affect stability somewhat. So can it be  done? 
Yes. Should it be done? That's up to the user to decide.
2) On the next batch of 10MHz DIP-14 TCXO units the external TCXO itself  
drives the output directly without a buffer. That TCXO is not capable of 
driving  50 Ohms inputs, only CMOS 1M Ohms inputs. So a buffer is required on 
these  10MHz units if 50 Ohms test equipment is to be used.
Hope that explains it,
In a message dated 11/17/2014 15:27:21 Pacific Standard Time,  
jim at jtmiller.com writes:

Hello Said

I got a nice surprise in my mail today: LTE-Lite!

There was a note with it that said (in effect) none of the outputs are  
50ohm capable. So it looks like I should build up a little board with the  
divide by two and incorporate on that a 50ohm capable buffer for clock  
transmission to the rest of my system?

BTW, you're welcome to answer via Timenuts as I'm sure others will have  
the same question.



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