Dear all,

I'm in the early stages of designing a board with a Virtex-4 FX on it 
which we are planning to use for development involving RocketIO.  The 
other guys on the team have stated that it would be "really useful" to 
have the clock for the RocketIO fed from a programmable oscillator.  We 
have a Virtex-II FX development board that has a similar arrangement, 
using a ICS8442 low jitter LVDS frequency synthesizer.  Does anyone have 
any suggestions or advice?  Can/Should I use the same device?  Is this a 
wild goose chase?

TIA

Peter

Peter

We use the ICS8442 and it has a very good jitter specification which is good 
for applications like RocketIO. When you are looking at this kind of 
specification there are not many devices as good as the ICS8442 especially 
if you want to use LVDS. The device is fairly layout sensative so do take 
care in that area of it but that's not unusual in this type of device.

John Adair
Enterpoint Ltd. - Home of Broaddown4. The Ultimate Virtex-4 Development 
Board.
http://www.enterpoint.co.uk


"Peter Mendham" <petermendham@NOCANNEDMEAT.computing.dundee.ac.uk> wrote in 
message news:eaq928$5j8$1@dux.dundee.ac.uk...
> Dear all,
>
> I'm in the early stages of designing a board with a Virtex-4 FX on it 
> which we are planning to use for development involving RocketIO.  The 
> other guys on the team have stated that it would be "really useful" to 
> have the clock for the RocketIO fed from a programmable oscillator.  We 
> have a Virtex-II FX development board that has a similar arrangement, 
> using a ICS8442 low jitter LVDS frequency synthesizer.  Does anyone have 
> any suggestions or advice?  Can/Should I use the same device?  Is this a 
> wild goose chase?
>
> TIA
>
> Peter 

John,

Thanks for your advice and for sharing your experience.  We had a bad 
experience with the development board (in other respects) so I didn't 
want to "borrow" any parts of their design without checking other 
people's experiences.

Thanks

Peter

John Adair wrote:
> We use the ICS8442 and it has a very good jitter specification which is good 
> for applications like RocketIO. When you are looking at this kind of 
> specification there are not many devices as good as the ICS8442 especially 
> if you want to use LVDS. The device is fairly layout sensative so do take 
> care in that area of it but that's not unusual in this type of device.
> 
> "Peter Mendham" <petermendham@NOCANNEDMEAT.computing.dundee.ac.uk> wrote in 
> message news:eaq928$5j8$1@dux.dundee.ac.uk...
 >> <snip>
>> a ICS8442 low jitter LVDS frequency synthesizer.  Does anyone have 
>> any suggestions or advice?  Can/Should I use the same device?  Is this a 
>> wild goose chase?