7 Series FPGAs SelectIO Resources User Guide www.xilinx.com 83
UG471 (v1.10) May 8, 2018
Supported I/O Standards and Terminations
Figure 1-62 shows a sample circuit illustrating a termination technique for differential
SSTL18 with bidirectional DCI termination. DIFF_SSTL18_II_DCI is the only available DCI
standard for bidirectional use signaling. The DCI versions of DIFF_SSTL18_I,
DIFF_SSTL15, DIFF_SSTL135, and DIFF_SSTL12 are only available for unidirectional
signaling. Use the T_DCI standards for bidirectional signaling of DIFF_SSTL15,
DIFF_SSTL135, and DIFF_SSTL12 with DCI termination.
X-Ref Target - Figure 1-62
Figure 1-62: Differential SSTL18 Class II with DCI Bidirectional Termination
Z
0
IOB
IOB
DIFF_SSTL18_II_DCI DIFF_SSTL18_II_DCI
V
CCO
= 1.8V
R
VRN
= 2Z
0
= 100Ω
R
VRP
= 2Z
0
= 100Ω
+
–
DCI
V
CCO
= 1.8V
R
VRN
= 2Z
0
= 100Ω
R
VRP
= 2Z
0
= 100Ω
DIFF_SSTL18_II_DCI
ug471_c1_52_121214
Z
0
DIFF_SSTL18_II_DCI
DIFF_SSTL18_II_DCI DIFF_SSTL18_II_DCI
V
CCO
= 1.8V
R
VRN
= 2Z
0
= 100Ω
R
VRP
= 2Z
0
= 100Ω
+
–
V
CCO
= 1.8V
R
VRN
= 2Z
0
= 100Ω
R
VRP
= 2Z
0
= 100Ω