ProASIC3 Flash Family FPGAs
Revision 13
2-27
Table 2-30 I/O Output Buffer Maximum Resistances1
Applicable to Standard I/O Banks
Standard
Drive Strength
RPULL-DOWN
(
)2
RPULL-UP
(
)3
3.3 V LVTTL / 3.3 V LVCMOS
2 mA
100
300
4 mA
100
300
6 mA
50
150
8 mA
50
3.3 V LVCMOS Wide Range4
100 A
Same as regular
3.3 V LVCMOS
Same as regular
3.3 V LVCMOS
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 VCCI, drive strength selection, temperature, and process. For board design
considerations and detailed output buffer resistances, use the corresponding IBIS models located at
2. R(PULL-DOWN-MAX) = (VOLspec) / IOLspec
3. R(PULL-UP-MAX) = (VCCImax – VOHspec) / IOHspec
4. All LVCMOS 3.3 V software macros support LVCMOS 3.3 V wide range as specified in the JESD-8B
specification.
Table 2-31 I/O Weak Pull-Up/Pull-Down Resistances
Minimum and Maximum Weak Pull-Up/Pull-Down Resistance Values
VCCI
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
3.3 V (wide range I/Os)
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)