Hacker-Friendly Clock-Generator Chips?

Eric Hertz wrote 10/23/2016 at 07:18 • 3 points

Do y'all have experience with these...?

We're talking the sort of chip where you can, say, send a configuration via I2C/SPI and the chip will generate an output-clock anywhere from 1MHz to 200MHz...

I tried looking for something at the #Common Parts Library, but didn't see any.

I've come across these guys http://www.silabs.com/products/timing/clock-generator/si5340-41/pages/si5340-41.aspx

They're quite a bit more sophisticated than I need... I just need one (adjustable) output-frequency, maybe 2-4 identical outputs. They're also not particularly-cheap and I'm not too fond of QFN. SOIC-8 seems like it'd be plenty for my needs.

Anyone know of a "hobbiest-friendly" device?

Even single-output would be OK... I could use e.g. a CY2305 clock-fanout chip for the rest.

Concerns: I don't know much about these devices, and there seems to be a bit of a learning-curve... Some/most are called "programmable" and have non-volatile-memory involved... so you have to, essentially, "flash" these things with "firmware"... For some, it seems, this is, then, a power-on *default* which can be changed via configuration-registers while it's running... Then, reboot, and it'll reuse the original "flashed" values. But other devices, it seems to me, are *also* called "programmable", and it seems to me, they actually "flash" the values whenever you change them. Not Good For My Project. (no mention of the number of write-cycles?).

And, frankly, I don't really need *that* many different clock-speeds, but I do need a wide range, so e.g. if there was a device with an 8-bit *parallel-interface* to select a divisor, or something, that'd be fine. (heh, now that I think about it, maybe I should just use a 200MHz crystal-oscillator and some counter/divider chips and call it a day... that'd probably be more within the spirit of my current project, anyhow...)

BUT I need at least a few options between 200MHz and 100MHz, and going all the way down to 1MHz or less, and I am definitely curious about these devices, especially if there's one that's easy-to-use and solder... the sorta device that's useful-enough to have in most hacker-boxes ready to throw into a project needing an arbitrary or changeable clock-frequency... (Yahknow, got an AVR, trying to overclock to its maximum... bump up that clock-generator's output-frequency in small steps... trying to output a specific frequency for VGA for one project and something else for another...? Why invest in several different crystal-oscillators with very specific frequencies if you can just use one of these and a 20MHz crystal?).

So... hacker-friendly clock-generators? Thought-points?