I/O Structure & Features
standards (e.g., SSTL-2) independently. If an I/O bank does not use
voltage-referenced standards, the VREF pins are available as user I/O
pins.
Each I/O bank can support multiple standards with the same VCCIO for
input and output pins. For example, when VCCIO is 3.3-V, a bank can
support LVTTL, LVCMOS, and 3.3-V PCI for inputs and outputs.
Voltage-referenced standards can be supported in an I/O bank using any
number of single-ended or differential standards as long as they use the
same VREF and a compatible VCCIO value.
MultiVolt I/O Interface
The Cyclone II architecture supports the MultiVolt I/O interface feature,
which allows Cyclone II devices in all packages to interface with systems
of different supply voltages. Cyclone II devices have one set of VCC pins
(VCCINT) that power the internal device logic array and input buffers that
use the LVPECL, LVDS, HSTL, or SSTL I/O standards. Cyclone II devices
also have four or eight sets of VCC pins (VCCIO) that power the I/O
output drivers and input buffers that use the LVTTL, LVCMOS, or PCI
I/O standards.
The Cyclone II VCCINT pins must always be connected to a 1.2-V power
supply. If the VCCINT level is 1.2 V, then input pins are 1.5-V, 1.8-V, 2.5-V,
and 3.3-V tolerant. The VCCIO pins can be connected to either a 1.5-V,
1.8-V, 2.5-V, or 3.3-V power supply, depending on the output
requirements. The output levels are compatible with systems of the same
voltage as the power supply (i.e., when VCCIO pins are connected to a
1.5-V power supply, the output levels are compatible with 1.5-V systems).
When VCCIO pins are connected to a 3.3-V power supply, the output high
is 3.3-V and is compatible with 3.3-V systems. Table 2–20 summarizes
Cyclone II MultiVolt I/O support.
Table 2–20. Cyclone II MultiVolt I/O Support (Part 1 of 2)
Note (1)
Input Signal
VCCIO (V)
Output Signal
1.8 V 2.5 V
1.5 V
1.8 V
2.5 V
3.3 V
1.5 V
v
v (3)
v (5)
3.3 V
1.5
1.8
2.5
v
v (4)
v
v
v (2)
v (2)
v
v (2)
v (2)
v
v
v
v (5)
2–60
Cyclone II Device Handbook, Volume 1
Altera Corporation
February 2007
ALTERA [ ALTERA CORPORATION ]
