
Altera Corporation
11–25
October 2007
Stratix II GX Device Handbook, Volume 2
High-Speed Differential I/O Interfaces with DPA in Stratix II & Stratix II GX Devices
Using Both Center Fast PLLs
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Both center fast PLLs can be used for DPA as long as they drive DPA
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Both center fast PLLs cannot be used for DPA if one of the fast PLLs
drives the top and bottom banks, or if they are driving cross banks
(e.g., the lower fast PLL drives the top bank and the top fast PLL
drives the lower bank).
Figure 11–23. Center Fast PLL Usage When Driving DPA Channels
Ref CLK
DPA
Fast PLL
Ref Clk
Center PLL
Driving Top Bank
Center PLL
Driving Lower Bank
Ref Clk
Channels Driven by
the Lower Center PLL
Channels Driven by
the Upper Center PLL