126.96.36.199. Differential I/O Termination for Intel® Arria® 10 Devices
The I/O pins are organized in pairs to support differential I/O standards. Each I/O pin pair can support differential input and output buffers.
The supported I/O standards such as Differential SSTL-12, Differential SSTL-15, Differential SSTL-125, and Differential SSTL-135 typically do not require external board termination.
Intel recommends that you use OCT with these I/O standards to save board space and cost. OCT reduces the number of external termination resistors used.