Other Important Design Notes; Powering The Rocketio X Transceivers; Powerdown Port; Figure 4-29: Ac-Coupled Serial Link - Xilinx RocketIO X User Manual

Other Important Design Notes

supports coded or scrambled data with run lengths of up to 72 bits for the entire range of
data rates (2.488– 10.3125 Gb/s). This AC coupling provides a high-pass filter with a corner
frequency of 100 kHz.
Capacitors of value 0.01 µF in a 0402 package are suitable for AC coupling up to
10.3125 Gb/s when 8B/10B or 64B/66B 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 X transceivers are
interfaced with other RocketIO X transceivers. Passive components are not required when
DC coupling is used. This is illustrated in
Other Important Design Notes

Powering the RocketIO X Transceivers

IMPORTANT! All RocketIO X transceivers in the FPGA, whether instantiated in the
design or not, must be connected to power and ground. Unused transceivers can be
powered by any 2.5V/1.5V source, and passive filtering is not required. Refer to
Conditioning," page 114
transceivers.
Maximum power consumption (PMA + PCS) per MGT is about 600 mW at 10.3125 Gb/s.
See

POWERDOWN Port

POWERDOWN is a single-bit primitive port (see
off the transceiver, in case it is not needed for the design or will not be transmitting or
receiving for a long period of time. When POWERDOWN is asserted, the transceiver does
not use any power. The clocks are disabled and do not propagate through the core. The
3-state TXP and TXN pins are set to high-Z, while the outputs to the fabric are frozen but
not set to high-Z.
Any given transceiver that is not instantiated in the design is automatically set to the
POWERDOWN state by the Xilinx ISE development software and consumes no power. An
instantiated transceiver, however, consumes some power, even if it is not engaged in
RocketIO™ X Transceiver User Guide
UG035 (v1.5) November 22, 2004
TX

Figure 4-29: AC-Coupled Serial Link

TX

Figure 4-30: DC-Coupled Serial Link

for detailed information on powering instantiated RocketIO X
Table 4-11 for more detail.
www.xilinx.com
1-800-255-7778
C
1
Z
0DIFF
C
2
ug035_ch4_24_022703
Figure 4-30.
Z
RX
0DIFF
ug035_ch4_28_092403
Table 3-1, page
RX
"Power
74) that allows shutting
121
R