Ken, Go to this site to check Si570 part numbers:

www.silabs.com/VCXOPartNumber

You may also want to download the relatively new V1.0 Si570 data
sheet, it is significantly updated.

In my opinion the +/-20ppm LVDS part via the FIN1002 transceiver is
the way to go due to somewhat better phase noise performance. But for
some (probably good) reason CMOS parts are being shipped with the
Softrock kits. Now you can get the FIN1002 included (at no additional
cost) only upon request when ordering a softrock kit.

My CMOS Si570's through the KM5H group-buy were +/-50ppm and have the
following specifications. I can't speak about the parts that come with
the Softrock kits.

Oscillator Part Number Information
DERIVED PART NUMBER: 570CAC000141DG
OSCILLATOR SPECIFICATION SUMMARY
11/10/2008 8:06:26 PM
Part Number: 570CAC000141DG
Model Number: Si570 (Programmable XO)
Output Format: CMOS
VDD: 3.3V
Output Enable Polarity: OE active high
Temperature Stability: +/- 50 ppm
Frequency Range: 10 - 160 MHz
Startup Frequency (MHz): 56.3200000
I2C Address: 55 hex (85 decimal)
Operating Temperature Range (°C): -40 to +85

Here are the +/-20ppm LVDS parts I got via the KM5H group buy:

DERIVED PART NUMBER: 570BBC000141DG
OSCILLATOR SPECIFICATION SUMMARY
11/10/2008 8:17:33 PM
Part Number: 570BBC000141DG
Model Number: Si570 (Programmable XO)
Output Format: LVDS
VDD: 3.3V
Output Enable Polarity: OE active high
Temperature Stability: +/- 20 ppm
Frequency Range: 10 - 215 MHz
Startup Frequency (MHz): 56.3200000
I2C Address: 55 hex (85 decimal)
Operating Temperature Range (°C): -40 to +85

Best 73's, David WB4ONA

----------------------------

--- In softrock40@yahoogroups.com, "sailingto" <sailingto@...> wrote:
>
> --- In softrock40@yahoogroups.com, "sailingto" <sailingto@> wrote:
> >
> > I know this has been covered before, but I lost the thread and
> could
> > not find it again even with the search fuction.
> >
> > What are the specs for the Si570 chip?
> >
> > I remember the voltage is 3.3V - I think.
> > I'm not sure about the Output Enable Polarity: is it high or low?
> >
> > Startup Frequency (MHz): 56.3200000 - seems like this might be the
> > range, but not sure
> >
> > I think I remember the I2C Address as being 55 hex - is this
> correct?
> >
> > Thanks for info,
> >
> > 73 de Ken H. K9FV
>
> I forgot to mention this is for the CMOS chip - isn't the general
> concenus this is best to use for the SR series rigs?
>
> Ken
>