Reference Clock; Epson Eg-2121Ca 2.5V (Lvpecl Outputs); Pletronics Lv1145B (Lvds Outputs); Figure 4-14: Dc-Coupled Serial Link - Xilinx RocketIO User Manual

R
Capacitors of value 0.01 µF in a 0402 package are suitable for AC coupling at 3.125 Gb/s
when 8B/10B encoding is used. Different data rates and different encoding schemes may
require a different value.
DC coupling (direct connection) is preferable in cases where RocketIO transceivers are
interfaced with other RocketIO transceivers or other Mindspeed transceivers that have
compatible differential and common mode voltage specifications. Passive components are
not required when DC coupling is used. This is illustrated in

Reference Clock

A high degree of accuracy is required from the reference clock. For this reason, it is
required that one of the oscillators listed in this section be used:

Epson EG-2121CA 2.5V (LVPECL outputs)

See the
circuit specified by the manufacturer must be used.
The circuit shown in
to the LVDS inputs of the transceiver reference clock.

Pletronics LV1145B (LVDS outputs)

See the
The circuit shown in
the LVDS inputs of the transceiver reference clock.
94
TX

Figure 4-14: DC-Coupled Serial Link

Epson Electronics America website
Figure 4-15
EG2121CA
2.5V-PECL
100Ω

Figure 4-15: LVPECL Reference Clock Oscillator Interface

Pletronics website for detailed information.
Figure 4-16
LV1145B
2.5V-LVDS

Figure 4-16: LVDS Reference Clock Oscillator Interface

www.xilinx.com
1-800-255-7778
Chapter 4: Analog Design Considerations
Z
0DIFF
UG024_24_020802
for detailed information. The power supply
must be used to interface the oscillator's LVPECL outputs
Z
0
100Ω
Z
0
100Ω
must be used to interface the oscillator's LVDS outputs to
Z
0
100Ω
Z
0
RocketIO™ Transceiver User Guide
Figure 4-14.
RX
LVDS
UG024_025a_050102
LVDS
UG024_025b_050102
UG024 (v1.5) October 16, 2002