
Detailed Specifications
2- 14
R e v i sio n 1 8
I/O Banks and Compatibility
Since each I/O bank has its own user-assigned input reference voltage (VREF) and an input/output
supply voltage (VCCI), only I/Os with compatible standards can be assigned to the same bank.
Table 2-11 shows the compatible I/O standards for a common VREF (for voltage-referenced standards).
Similarly,
Table 2-12 shows compatible standards for a common VCCI.
Table 2-11 Compatible I/O Standards for Different VREF Values
VREF
Compatible Standards
1.5 V
SSTL 3 (Class I and II)
1.25 V
SSTL 2 (Class I and II)
1.0 V
GTL+ (2.5V and 3.3V Outputs)
0.75 V
HSTL (Class I)
Table 2-12 Compatible I/O Standards for Different VCCI Values
VCCI1
Compatible Standards
VREF
3.3 V
LVTTL, PCI, PCI-X, LVPECL, GTL+ 3.3 V
1.0
3.3 V
SSTL 3 (Class I and II), LVTTL, PCI, LVPECL
1.5
2.5 V
LVCMOS 2.5 V, GTL+ 2.5 V, LVDS2
1.0
2.5 V
LVCMOS 2.5 V, SSTL 2 (Classes I and II), LVDS2
1.25
1.8 V
LVCMOS 1.8 V
N/A
1.5 V
LVCMOS 1.5 V, HSTL Class I
0.75
Notes:
1. VCCI is used for both inputs and outputs
2. VCCI tolerance is
±5%