ProASIC3 DC and Switching Characteristics
v1.3 2-25
Table 2-30 • I/O Output Buffer Maximum Resistances
1
Applicable to Standard I/O Banks
Standard Drive Strength
R
PULL-DOWN
(Ω)
2
R
PULL-UP
(Ω)
3
3.3 V LVTTL / 3.3 V LVCMOS 2 mA 100 300
4 mA 100 300
6 mA 50 150
8 mA 50 150
2.5 V LVCMOS 2 mA 100 200
4 mA 100 200
6 mA 50 100
8 mA 50 100
1.8 V LVCMOS 2 mA 200 225
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 V
CCI
, drive strength selection, temperature, and process. For
board design considerations and detailed output buffer resistances, use the corresponding
IBIS models located on the Actel website at http://www.actel.com/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 2-31 • I/O Weak Pull-Up/Pull-Down Resistances
Minimum and Maximum Weak Pull-Up/Pull-Down Resistance Values
V
CCI
R
(WEAK PULL-UP)
1
(Ω)
R
(WEAK PULL-DOWN)
2
(Ω)
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)
= (V
OLspec
) / I
(WEAK PULL-UP-MIN)
2. R
(WEAK PULL-UP-MAX)
= (V
CCImax
– V
OHspec
) / I
(WEAK PULL-UP-MIN)
