When I last ordered a pile of Crazy Clocks to be manufactured, I screwed up and ordered a reel of PAM2305 buck converters (they're used in the GPS clock and the Pi clock projects) by mistake instead of XC9140 boost converters. Since they were ordered as DigiReels, they're not returnable, so I'm sort of stuck with a lifetime supply of them.

Well, they're good chips... could they replace the SC189Z that I've been using in the GPSDO?

Turns out that the answer appears to be yes. I built a board with one (it's pin compatible with the SC189Z) using the part values I've been using for the GPS clock. It seems to have nice low noise and ripple. It's going to take a few days run time for the oscillator to stabilize to get a good picture, but it looks good right at the start.