
Virtex-II Platform FPGAs: Functional Description
R
DS031-2 (v3.5) November 5, 2007
Module 2 of 4
Product Specification
10
Figure 12 provides examples illustrating the use of the SSTL2_I_DCI, SSTL2_II_DCI, SSTL3_I_DCI, and SSTL3_II_DCI I/O
Figure 12: SSTL DCI Usage Examples
DS031_65b_112502
Conventional
DCI Transmit
Conventional
Receive
Conventional
Transmit
DCI Receive
DCI Transmit
DCI Receive
Bidirectional
Reference
Resistor
Recommended
Z0
(2)
VRN = VRP = R = Z0
50
Ω
VRN = VRP = R = Z0
50
Ω
VRN = VRP = R = Z0
50
Ω
VRN = VRP = R = Z0
50
Ω
SSTL2_I
SSTL2_II
SSTL3_I
SSTL3_II
N/A
Virtex-II DCI
Z0
R
VCCO/2
Z0
R/2
RR
VCCO/2
Z0
R/2
RR
VCCO/2
Z0
R/2
R
VCCO/2
Z0
R/2
R
VCCO/2
Z0
R/2
Virtex-II DCI
2R
VCCO
R
VCCO/2
Z0
R/2
Virtex-II DCI
2R
VCCO
Z0
R/2
Virtex-II DCI
2R
VCCO
Z0
R/2
Virtex-II DCI
2R
VCCO
Virtex-II DCI
R
VCCO
VCCO/2
2R
Virtex-II DCI
R
VCCO
VCCO/2
2R
Virtex-II DCI
R
VCCO/2
Z0
Virtex-II DCI
R
VCCO/2
Z0
2R
Virtex-II DCI
2R
VCCO
Virtex-II DCI
2R
VCCO
Z0
Virtex-II DCI
2R
VCCO
Z0
2R
Virtex-II DCI
2R
VCCO
Virtex-II DCI
2R
VCCO
Z0
Virtex-II DCI
2R
VCCO
Virtex-II DCI
Z0
Virtex-II DCI
2R
VCCO
2R
VCCO
Virtex-II DCI
Z0
Virtex-II DCI
2R
VCCO
2R
VCCO
25
Ω(
1)
25
Ω(
1)
25
Ω(
1)
25
Ω(
1)
25
Ω(
1)
25
Ω(
1)
25
Ω(
1)
25
Ω(
1)
25
Ω(
1)
25
Ω(
1)
25
Ω(
1)
25
Ω(
1)
Notes:
1. The SSTL-compatible 25
Ω series resistor is accounted for in the DCI buffer, and it is not DCI controlled.
2. Z0 is the recommended PCB trace impedance.