afs600 Actel Corporation, afs600 Datasheet - Page 145

• Manufacturer Part Number: afs600
• Description: Actel Fusion Programmable System Chips Mixed-signal Family With Optional Arm Support
• Manufacturer: Actel Corporation

Solution 3
The board-level design must ensure that the reflected waveform at the pad does not exceed limits provided in
Table 3-4 on page
This scheme will also work for a 3.3 V PCI/PCIX configuration, but the internal diode should not be used for clamping,
and the voltage must be limited by the bus switch, as shown in
create an excessive pad DC voltage of 3.3 V + 0.7 V = 4 V.
Figure 2-97 • Solution 3
3-4. This is a long-term reliability requirement.
5.5 V
5.5 V
Bus
Switch
IDTQS32X23
Off-Chip
Requires a bus switch on the board,
LVTTL/LVCMOS 3.3 V I/Os.
A d v an c ed v1 . 4
Solution 3
On-Chip
Fusion I/O Input
Figure
3.3 V
2-97. Relying on the diode clamping would
Actel Fusion Programmable System Chips
2-131