SmartFusion Customizable System-on-Chip (cSoC)
Revision 10 2-27
Table 2-28 • I/O Output Buffer Maximum Resistances
1
Applicable to MSS I/O Banks
Standard Drive Strength
R
PULL-DOWN
()
2
R
PULL-UP
()
3
3.3 V LVTTL / 3.3 V LVCMOS 8mA 50 150
2.5 V LVCMOS 8 mA 50 100
1.8 V LVCMOS 4 mA 100 112
1.5 V LVCMOS 2 mA 200 224
Notes:
1. These maximum values are provided for informational reasons only. Minimum output buffer resistance
values depend on VCCxxxxIOBx, drive strength selection, temperature, and process. For board design
considerations and detailed output buffer resistances, use the corresponding IBIS models located on the
SoC Products Group website at http://www.microsemi.com/soc/download/ibis/default.aspx.
2. R
(PULL-DOWN-MAX)
= (V
OLspec
) / I
OLspec
3. R
(PULL-UP-MAX)
= (V
CCImax
– V
OHspec
) / I
OHspec
Table 2-29 • I/O Weak Pull-Up/Pull-Down Resistances
Minimum and Maximum Weak Pull-Up/Pull-Down Resistance Values
VCCxxxxIOBx
R
(WEAK PULL-UP)
1
()
R
(WEAK PULL-DOWN)
2
()
Min. Max. Min. Max.
3.3 V 10 k 45 k 10 k 45 k
2.5 V 11 k 55 k 12 k 74 k
1.8 V 18 k 70 k 17 k 110 k
1.5 V 19 k 90 k 19 k 140 k
Notes:
1. R
(WEAK PULL-UP-MAX)
= (VCCImax – VOHspec) / I
(WEAK PULL-UP-MIN)
2. R
(WEAK PULL-DOWN-MAX)
= (VOLspec) / I
(WEAK PULL-DOWN-MIN)
