EP1S20F672C7N Datasheet, PDF (452/864 Pages) List of Unclassifed Manufacturers – Stratix Device Handbook, Volume 1

Stratix & Stratix GX I/O Banks
Non-Voltage-Referenced Standards
Each Stratix I/O bank has its own VCCIO pins and supports only one
V_CCIO, either 1.5, 1.8, 2.5 or 3.3 V. A Stratix I/O bank can simultaneously
support any number of input signals with different I/O standard
assignments, as shown in Table 4–5.
Table 4–5. Acceptable Input Levels for LVTTL/LVCMOS
Bank V_CCIO
3.3 V
2.5 V
1.8 V
1.5 V
3.3 V
v
v
v (2)
v (2)
Acceptable Input Levels
2.5 V
1.8 V
v
v
v (2)
v
v (2)
v
1.5 V
v (1)
v
Notes to Table 4–5:
(1) Because the input signal will not drive to the rail, the input buffer does not
completely shut off, and the I/O current will be slightly higher than the default
value.
(2) These input values overdrive the input buffer, so the pin leakage current will be
slightly higher than the default value.
For output signals, a single I/O bank can only support non-voltage-
referenced output signals driving at the same voltage as V_CCIO. A Stratix
I/O bank can only have one V_CCIO value, so it can only drive out that one
value for non-voltage referenced signals. For example, an I/O bank with
a 2.5-V V_CCIO setting can support 2.5-V LVTTL inputs and outputs,
HyperTransport technology inputs and outputs, and 3.3-V LVCMOS
inputs (not output or bidirectional pins).
1 If the output buffer overdrives the input buffer, you must turn
on the Allow voltage overdrive for LVTTL/LVCMOS option in
the Quartus II software. To see this option, click the Device &
Pin Options button in the Device page of the Settings dialog
box (Assignments menu). Then click the Pin Placement tab in
the Device & Pin Options dialog box.
Voltage-Referenced Standards
To accommodate voltage-referenced I/O standards, each Stratix I/O
bank supports multiple VREF pins feeding a common VREF bus. The
number of available VREF pins increases as device density increases. If
these pins are not used as VREF pins, they can not be used as generic I/O
pins.
4–24
Stratix Device Handbook, Volume 2
Altera Corporation
June 2006