EP3C16F256I7N Altera, EP3C16F256I7N Datasheet - Page 187

• Manufacturer Part Number: EP3C16F256I7N
• Description: Cyclone III
• Manufacturer: Altera

Altera Corporation-Preliminary
March 2007
If the bidirectional pads are all controlled by the same output enable (OE)
and there are no other outputs or voltage referenced inputs in the bank,
there would be no case where a voltage referenced input is active at the
same time as an output. Therefore, the output limitation does not apply.
However, since the bidirectional pads are linked to the same OE, all the
bidirectional pads act as inputs at the same time. Therefore, the input
limitation of 32 input pads (per V
21 input pads (per V
If the bidirectional pads are all controlled by different OEs, and there are
no other outputs or voltage referenced inputs in the bank, there may be a
case where one group of bidirectional pads is acting as inputs while
another group is acting as outputs. In such cases, apply the formulas
shown in
When at least one additional voltage referenced input and no other
outputs exist in the same V
applies in addition to the input and output limitations. See the following
equations:
FineLine BGA
QFP
Table 7–9. Input-Only Bidirectional Pad Limitation Formulas
Package Type
Total number of bidirectional pads + total number of input pads
for Fineline BGA packages
Total number of bidirectional pads + total number of input pads
for QFP packages
Table
7–9.
(Total number of bidirectional pads) – (Total number of pads
from the smallest group of pads controlled by an OE) ≤ 9 (per
V
(Total number of bidirectional pads) – (Total number of pads
from the smallest group of pads controlled by an OE) ≤ 5 (per
V
CCIO
CCIO
REF
and ground pair)
and ground pair)
pad) for QFP packages applies.
REF
bank, the bidirectional pad limitation
REF
Cyclone III Device Handbook, Volume 1
pad) for FineLine BGA packages and
Pad Placement and DC Guidelines
Formula
7–35
≤ 32
≤ 21