ML365 Virtex-II Pro QDR II SRAM Mem. Board
www.xilinx.com
41
UG066 (v1.0) June 29, 2004
1-800-255-7778
Clock Signal Simulations
R
Clock Signal Simulations
The simulations in this subsection test the uni-directional Clock K signal from the FPGA to
the QDR II SRAM, Component B. Simulations were performed for the following cases:
typical, slow/weak, and fast/strong. All of the clock signal simulations use the following
test conditions for typical, slow/weak, and fast/strong cases (refer to
).
•
Topology for clock signals: 50-ohm transmission lines
•
Clock K
♦
At the memory: 100-ohm parallel split termination pulled-up to V
dd
= 1.8 V
(equivalent to a 50-ohm termination pulled up to V
ref
= 0.9V)
♦
At the FPGA: HSTL_18_C2 drivers
•
CQ Clock
♦
At the FPGA: HSTL_18_C1 receivers, 100-ohm parallel split termination pulled-
up to V
dd
= 1.8 V (equivalent to a 50-ohm termination pulled up to V
ref
= 0.9V)
Figure 4-6:
Clock Signal Terminations
ml365_02_062804
QDR II SRAM
QDR II SRAM
FPGA
FPGA
Vdd
Vdd
CQ Clock
K Clock
Product Not Recommended for New Designs