[time-nuts] Ublox 8T - breakout board

[Matthias Welwarsky]

Dear all,

I've received quite a number of emails with feedback, thank you very much for 
your interest and participation. I'll not respond to the individual mails so 
here's a summary:

* Will the design files be public: Yes, you can find a Work-In-Progress state 
of the complete development project here: https://github.com/thinkfat/ublox-breakout. It's a KiCAD 5 project, but there's a "fab" folder that contains 
Gerber files and BOM and CPL files for JLCPCB SMT. THIS IS NOT THE FINAL 
DESIGN REVISION!

* Thanks for the LDO suggestion, I'll have a look at them.

* Buffered PPS output + SMA footprint: While it may not appear so, the board 
is quite densely populated and SMA connectors are rather large. I'm checking 
if I can afford to make the board a bit larger. Thanks for suggesting the 
74HC244.

* Symmetric mounting holes: I reshuffled the layout a bit, that will work out 
fine.

* Backup battery: I consider that not a priority for a timing receiver. 
However: a Keystone mounting bracket for a CR1220 battery would fit on the 
backside, but I need to find out how to make that optional, the backup supply 
pin must be connected to the main power supply if not equipped. Maybe a couple 
of diodes are sufficient to prevent back-feeding the battery from the main 
3.3V.

* Pull-Up resistors for the I2C: OK

* D_SEL on the pin header: OK

Attached a screenshot of the current layout.

BR,
Matthias
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