1.17. Fractional Synthesis PLLs and I/O PLLs
Intel® Stratix® 10 MX devices have up to 32 fractional synthesis PLLs (fPLL) available for use with transceivers or in the core fabric.
The fPLLs are located in the 3D SiP transceiver L-tiles and H-tiles, eight per tile, adjacent to the transceiver channels. The fPLLs can be used to reduce both the number of oscillators required on the board and the number of clock pins required, by synthesizing multiple clock frequencies from a single reference clock source. In addition to synthesizing reference clock frequencies for the transceiver transmit PLLs, the fPLLs can also be used directly for transmit clocking. Each fPLL can be independently configured for conventional integer mode, or enhanced fractional synthesis mode with third-order delta-sigma modulation.
In addition to the fPLLs, Intel® Stratix® 10 MX devices contain 16 integer I/O PLLs (IOPLLs) available for general purpose use in the core fabric and for simplifying the design of external memory interfaces and high-speed LVDS interfaces. The IOPLLs are located in each bank of 48 general purpose I/O, one per I/O bank, adjacent to the hard memory controllers and LVDS SerDes in each I/O bank. This makes it easier to close timing because the IOPLLs are tightly coupled with the I/Os that need to use them. The IOPLLs can be used for general purpose applications in the core such as clock network delay compensation and zero-delay clock buffering.