"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
Ah, gotcha -- I wans't thinking (the really rather obvious bit) that there's no such thing as a 1575.42MHz crystal. :-)
Speaking of PLLs... do you happen to know why so many of them have rather high (hundreds of MHz) lower frequency limits? E.g., this seemingly-popular part:
Discussions at work here and with Joerg have postulated:
-- AC coupling of the input amplifiers?
-- The fastest counters (dividers) are actually dynamic circuitry, and hence they really can't count too slowly or they forget where they were. (1, 2,
3... umm? 3? 1? Where was I again? La-la-la-la-la I'm so confused!)There aren't a lot of low-power PLL-based synthesizers in the "more than a handful of MHz"-CD4046 (and derivative) territory and these multi-hundred-MHz+ monsters. We're after some 45MHz PLLs, and so far the ADF4001 is one of the very few attractive-looking candidates.
Thanks for the help,
---Joel