Si580 Group buy Output levels, Temp Stability Options
- Hi Tom,
Thanks so much for helping with the group buy of the Si570.
I had a couple of comments on the order specification.
The new group buy web page shows the LVDS phase noise performance but
the parts you bought are the CMOS version. Not sure which way the
group buy is going.
My input would be to buy the 1st Option Code: B or N code which is the
3.3V LVDS (High or Low OE not important to me). The spec sheet shows
the LVDS phase noise performance which is excellent. The CMOS version
probably isn't that great since the edge speeds are 1ns typical ( the
LVDS and others is 350 ps max ). Also to get an indication of phase
noise performance SI has an AN291 describing the Output Buffer
Options. As shown in Figure 7 CMOS has the poorest jitter performance
(translation to phase noise). The figure also shows that CML and
LVPECL would offer the best phase noise performance. I would still
choose LVDS because of it's ease of use, low power consumption, and
very common standard in newer designs.
One other consideration would be the 2nd Option Code. My choice would
be The code B option which is 31.5ppm total stability (compared to the
code A option which is 61.5ppm). Since we are using these for our
radio frequency control, I think I would be worth an addition cost to
get the higher stability. I don't know if you have priced the
difference but it sure would be worth considering.
As far a initial freq. I don't care that much. I like that most have
wanted it to be for 20M (i.e. 56Mhz++). If I had to select (for my
most used mode SSB) I would select 57Mhz. Of course there will be
many opinions on this.
Thanks for the consideration of LVDS output and high stability in the
What do others think? Don't you want the better phase noise
performance and stability??
Thanks, Mike Collins KF4BQ
- ----- Original Message -----From: k5nwaSent: Thursday, January 10, 2008 7:27 PMSubject: Re: [softrock40] Si570 PCBAt 01:41 AM 1/9/2008, you wrote:
Here's the schematic for an Si570 PCB I'm working on:
The board includes a PIC16LF88 MCU, with a 3.3V LDO regulator, and has
connectors for a rotary encoder and two pushbuttons. It's mostly
surface-mount, and being single-sided will be easy to make at home. Size is
1.325" x 2.15".
Is that a ICSP connector to program the chip? Or is it some other standard.Yes, it's for an ICD 2 debugger/programmer.73, Leon