188.8.131.52. PLLs Driving DPA-Enabled Differential Receiver Channels
Each differential receiver in an I/O bank has a dedicated DPA circuit to align the phase of the clock to the data phase of its associated channel. If you enable a DPA channel in a bank, you can assign the unused I/O pins in the bank to single-ended or differential I/O standards that has the same VCCIO voltage level used by the bank.
DPA usage adds some constraints to the placement of high-speed differential receiver channels. The Intel® Quartus® Prime compiler automatically checks the design and issues error messages if there are placement guidelines violations. Adhere to the guidelines to ensure proper high-speed I/O operation.