XC2VP70 Xilinx, Inc., XC2VP70 Datasheet - Page 32

• Manufacturer Part Number: XC2VP70
• Description: Virtex-ii Pro Field Programmable Gate Array
• Manufacturer: Xilinx, Inc.

Figure 21
LVDS_25_DCI and LVDSEXT_25_DCI I/O standards. For a
complete list, see the Virtex-II Pro Platform FPGA User
Guide.
On-Chip Differential Termination
Virtex-II Pro provides a true 100Ω differential termination
(DT) across the input differential receiver terminals. The
LVDS_25_DT,
ULVDS_25_DT standards support on-chip differential termi-
nation.
DS083-2 (v2.9) October 14, 2003
Advance Product Specification
Recommended
Z 0
Conventional
Conventional
Transmit
DCI Receive
Reference
Resistor
Figure 21: LVDS DCI Usage Examples
provides examples illustrating the use of the
R
NOTE: Only LVDS25_DCI is supported (V
LVDS_25_DCI and LVDSEXT_25_DCI Receiver
LVDSEXT_25_DT,
VRN = VRP = R = Z 0
Z 0
Z 0
Z 0
Z 0
50 Ω
V
V
CCO
LDT_25_DT,
CCO
CCO
2R
2R
2R
= 2.5V only)
2R
2R
Virtex-II Pro
LVDS DCI
DS083-2_65c_022103
Virtex-II Pro
LVDS
www.xilinx.com
1-800-255-7778
and
The on-chip input differential termination in Virtex-II Pro
provides major advantages over the external resistor or the
DCI termination solution:
•
•
•
•
Figure 22
LVDS_25_DT,
ULVDS_25_DT I/O standards. For further details, refer to
Solution Record
form FPGA User Guide
Virtex-II Pro™ Platform FPGAs: Functional Description
Recommended
Z 0
Conventional
Conventional
Transmit,
On-Chip
Differential
Termination
Receive
Eliminates the stub at the receiver completely and
therefore greatly improve signal integrity
Consumes less power than DCI termination
Supports LDT (not supported by DCI termination)
Frees up VRP/VRN pins
Figure 22: LVDS Differential Termination Usage
provides examples illustrating the use of the
NOTE: Only 2.5V LVDS standards are supported (V
LVDSEXT_25_DT,
LDT_25_DT, and ULVDS_25_DT Receiver
17244. Also see the
LVDS_25_DT, LVDSEXT_25_DT,
Examples
for more design information.
Z 0
Z 0
Z 0
Z 0
50 Ω
100Ω
LDT_25_DT,
2R
Virtex-II Pro Plat-
Virtex-II Pro
LVDS On-Chip
Differential
Termination
CCO
DS083-2_65e_052703
Virtex-II Pro
LVDS
= 2.5V only)
and
23