[time-nuts] DS-1 from 10MHz

Tom Clifton kc0vsj at yahoo.com
Tue Jul 6 03:32:25 UTC 2010


I'm running more than a few days late on mail, but my inclination would be to order a custom programmed SI5355 from Silicon Labs for $5 - no minimum quantity and 2 week turnaround.  Admittedly the part is a qfn (SMT Quad Flat-pack No-leads) but it is easy, can run off an external user provided reference clock, and has reasonable jitter ('typically 50ps - not as good as an SI570 but a whole lot better than an AD9851 DDS), and for a T1 clock should be perfectly suitable.

From the Silabs page:

The Si5355 is a highly flexible clock generator capable of synthesizing four
completely non-integer related frequencies up to 200 MHz. The device has four
banks of outputs with each bank supporting two CMOS outputs at the same
frequency. Using Silicon Laboratories' patented MultiSynth fractional divider
technology, all outputs are guaranteed to have 0 ppm frequency synthesis error
regardless of configuration, enabling the replacement of multiple clock ICs and
crystal oscillators with a single device. Through a flexible web configuration utility
called ClockBuilder™ (www.silabs.com/ClockBuilder), factory-customized pincontrolled
Si5355 devices are available in two weeks without minimum order
quantity restrictions. The Si5355 supports up to three independent, pin-selectable
device configurations, enabling one device to replace three separate clock ICs.


      





More information about the Time-nuts_lists.febo.com mailing list