DS681 Datasheet, PDF (26/56 Pages) Xilinx, Inc – Fast look-ahead carry logic

Output Timing Adjustments
Table 25: Output Timing Adjustments for IOB
Convert Output Time from
LVCMOS25 with 12mA Drive and
Fast Slew Rate to the Following
Signal Standard (IOSTANDARD)
Add the
Adjustment
Below
Speed Grade
-4
Single-Ended Standards
LVTTL
Slow 2 mA
5.58
4 mA
3.45
6 mA
3.45
8 mA
2.26
12 mA
1.66
16 mA
1.29
24 mA
2.97
Fast 2 mA
3.37
4 mA
2.27
6 mA
2.27
8 mA
0.63
12 mA
0.61
16 mA
0.59
24 mA
0.60
QuietIO 2 mA
27.67
4 mA
27.67
6 mA
27.67
8 mA
16.71
12 mA
16.67
16 mA
16.22
24 mA
12.11
Units
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
R
Table 25: Output Timing Adjustments for IOB (Continued)
Convert Output Time from
LVCMOS25 with 12mA Drive and
Fast Slew Rate to the Following
Signal Standard (IOSTANDARD)
Add the
Adjustment
Below
Speed Grade
-4
Units
LVCMOS33
Slow 2 mA
5.58
ns
4 mA
3.30
ns
6 mA
3.30
ns
8 mA
2.26
ns
12 mA
1.29
ns
16 mA
1.22
ns
24 mA
2.79
ns
Fast 2 mA
3.72
ns
4 mA
2.05
ns
6 mA
2.08
ns
8 mA
0.53
ns
12 mA
0.59
ns
16 mA
0.59
ns
24 mA
0.51
ns
QuietIO 2 mA
27.67
ns
4 mA
27.67
ns
6 mA
27.67
ns
8 mA
16.71
ns
12 mA
16.29
ns
16 mA
16.18
ns
24 mA
12.11
ns
26
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DS681 (v1.1) February 3, 2009
Product Specification