AD484 user manual
V1.2
AD484 User manual
February 2007
www.4dsp.com
- 16 -
3.6 Front Panel optical transceivers
Four 2.5Gb/s optical transceivers (LTP-ST11M) are available on the AD484 in the front panel
area. They are connected to the MGT I/Os of the Virtex-4 device A. Infiniband protocols as
well as Gigabit Ethernet and Fibre channel (sFPDP) can be implemented over the
transceivers. Lower rate optical transceivers (2.125Gb/s and 1.0625Gb/s) are available in the
same form factor.
Two low jitter clocks (106.25MHz and 125MHz) are directly connected to the MGT clock
inputs so multi-rate applications can be implemented on the AD484.
The MGT banks have power supplies independent from the digital supply provided to the
FPGAs in order to insure low noise and data integrity. The LT1963 device will be used to
generate the 1.2V, 1.5V and 2.5V necessary for the MGT to operate. The power filtering
network includes a 220nF decoupling capacitor and ferrite bead (MP21608S221A) per power
pin.
The signal differential pairs are routed on a specific inner layer with one reference GND
plane on each side of the layer stack up.
The optical transceivers are an ideal communication link to transfer digitized and processed
data to a remote system (eg, storage system) by offering an aggregate bandwidth of
1.25GBytes/s.
Figure 8: Optical transceivers
