System Specification
Device Selection
Early System and Board Planning
Pin Connection Considerations for Board Design
I/O and Clock Planning
Design Entry
Design Implementation, Analysis, Optimization, and Verification
Design Checklist
Appendix: Cyclone® 10 GX Transceiver Design Guidelines
Conclusion
Document Revision History
I/O Simultaneous Switching Noise
| Number | Done? | Checklist Item |
|---|---|---|
| 1 | Analyze the design for possible SSN problems. | |
| 2 | Reduce the number of pins that switch the voltage level at exactly the same time whenever possible. | |
| 3 | Use differential I/O standards and lower-voltage standards for high-switching I/Os. | |
| 4 | Use lower drive strengths for high-switching I/Os. The default drive strength setting might be higher than your design requires. | |
| 5 | Reduce the number of simultaneously switching output pins within each bank. Spread output pins across multiple banks if possible. | |
| 6 | Spread switching I/Os evenly throughout the bank to reduce the number of aggressors in a given area to reduce SSN (when bank usage is substantially below 100%). | |
| 7 | Separate simultaneously switching pins from input pins that are susceptible to SSN. | |
| 8 | Place important clock and asynchronous control signals near ground signals and away from large switching buses. | |
| 9 | Avoid using I/O pins one or two pins away from PLL power supply pins for high-switching or high-drive strength pins. | |
| 10 | Use staggered output delays to shift the output signals through time, or use adjustable slew rate settings. |
SSN is a concern when too many I/Os (in close proximity) change voltage levels at the same time. Plan the I/O and clock connections according to the recommendations.
For more information, refer to “ Cyclone® 10 GX I/O Features” for details about the features you can use.
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