Stratix GX Architecture
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 (for example, when VCCIOpins are connected to a 1.5-V
power supply, the output levels are compatible with 1.5-V systems).
When VCCIOpins are connected to a 3.3-V power supply, the output high
is 3.3 V and is compatible with 3.3-V or 5.0-V systems.
Table 4–32 summarizes Stratix GX MultiVolt I/O support.
Table 4–32. Stratix GX MultiVolt I/O Support
Input Signal (5)
1.5 V 1.8 V 2.5 V 3.3 V 5.0 V 1.5 V 1.8 V 2.5 V 3.3 V 5.0 V
Note (1)
Output Signal (6)
VCCIO (V)
1.5
1.8
2.5
3.3
v
v (2)
v
v
v
v (3)
v (3) v (3)
v (2) v (2)
v (2) v (2)
v
v
v
v
v
v
v
v (2)
v (4) v (3) v (3) v (3)
Notes to Table 4–32:
(1) To drive inputs higher than VCCIO but less than 4.1 V, disable the PCI clamping diode. However, to drive 5.0-V
inputs to the device, enable the PCI clamping diode to prevent VI from rising above 4.0 V.
(2) The input pin current may be slightly higher than the typical value.
(3) Although VCCIO specifies the voltage necessary for the Stratix GX device to drive out, a receiving device powered
at a different level can still interface with the Stratix GX device if it has inputs that tolerate the VCCIO value.
(4) Stratix GX devices can be 5.0-V tolerant with the use of an external resistor and the internal PCI clamp diode.
(5) This is the external signal that is driving the Stratix GX device.
(6) This represents the system voltage that Stratix GX supports when a VCCIO pin is connected to a specific voltage
level. For example, when VCCIO is 3.3 V and if the I/O standard is LVTTL/LVCMOS, the output high of the signal
coming out from Stratix GX is 3.3 V and is compatible with 3.3-V or 5.0-V systems.
Because Stratix GX devices can be used in a mixed-voltage environment,
they have been designed specifically to tolerate any possible power-up
sequence. Therefore, the VCCIOand VCCINTpower supplies may be
powered in any order.
Power
Sequencing &
Hot Socketing
Signals can be driven into Stratix GX devices before and during power up
without damaging the device. In addition, Stratix GX devices do not
drive out during power up. Once operating conditions are reached and
the device is configured, Stratix GX devices operate as specified by the
user. For more information, see the Selectable I/O Standards in Stratix &
Stratix GX Devices chapter of the Stratix GX Device Handbook, Volume 2.
Altera Corporation
February 2005
4–121
Stratix GX Device Handbook, Volume 1
ALTERA [ ALTERA CORPORATION ]
